diff --git a/ast.c b/ast.c
index a8634c8..6d3b123 100644
--- a/ast.c
+++ b/ast.c
@@ -26,6 +26,8 @@ const char* SyntaxKindString(SyntaxKind syntaxKind)
         case Comment: return "Comment";
         case Declaration: return "Declaration";
         case DeclarationSequence: return "DeclarationSequence";
+        case FunctionArgumentSequence: return "FunctionArgumentSequence";
+        case FunctionCallExpression: return "FunctionCallExpression";
         case FunctionDeclaration: return "FunctionDeclaration";
         case FunctionSignature: return "FunctionSignature";
         case FunctionSignatureArguments: return "FunctionSignatureArguments";
@@ -239,6 +241,36 @@ Node* MakeDeclarationSequenceNode(
     return node;
 }
 
+Node *MakeFunctionArgumentSequenceNode(
+    Node **pArgumentNodes,
+    uint32_t argumentCount
+) {
+    int32_t i;
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = FunctionArgumentSequence;
+    node->childCount = argumentCount;
+    node->children = (Node**) malloc(sizeof(Node*) * node->childCount);
+    for (i = argumentCount - 1; i >= 0; i -= 1)
+    {
+        node->children[argumentCount - 1 - i] = pArgumentNodes[i];
+    }
+    return node;
+}
+
+Node* MakeFunctionCallExpressionNode(
+    Node *identifierNode,
+    Node *argumentSequenceNode
+) {
+    int32_t i;
+    Node* node = (Node*) malloc(sizeof(Node));
+    node->syntaxKind = FunctionCallExpression;
+    node->children = (Node**) malloc(sizeof(Node*) * 2);
+    node->childCount = 2;
+    node->children[0] = identifierNode;
+    node->children[1] = argumentSequenceNode;
+    return node;
+}
+
 static const char* PrimitiveTypeToString(PrimitiveType type)
 {
     switch (type)
@@ -262,6 +294,10 @@ static void PrintBinaryOperator(BinaryOperator expression)
         case Subtract:
             printf("-");
             break;
+
+        case Multiply:
+            printf("*");
+            break;
     }
 }
 
@@ -308,5 +344,3 @@ void PrintTree(Node *node, uint32_t tabCount)
         PrintTree(node->children[i], tabCount + 1);
     }
 }
-
-
diff --git a/ast.h b/ast.h
index 6dd42ad..595f53f 100644
--- a/ast.h
+++ b/ast.h
@@ -12,6 +12,8 @@ typedef enum
     DeclarationSequence,
     Expression,
     ForLoop,
+    FunctionArgumentSequence,
+    FunctionCallExpression,
     FunctionDeclaration,
     FunctionSignature,
     FunctionSignatureArguments,
@@ -33,7 +35,8 @@ typedef enum
 typedef enum
 {
     Add,
-    Subtract
+    Subtract,
+    Multiply
 } BinaryOperator;
 
 typedef enum
@@ -130,6 +133,14 @@ Node* MakeDeclarationSequenceNode(
     Node **pNodes,
     uint32_t nodeCount
 );
+Node *MakeFunctionArgumentSequenceNode(
+    Node **pArgumentNodes,
+    uint32_t argumentCount
+);
+Node* MakeFunctionCallExpressionNode(
+    Node *identifierNode,
+    Node *argumentSequenceNode
+);
 
 void PrintTree(Node *node, uint32_t tabCount);
 
diff --git a/compiler.c b/compiler.c
index 98b4e30..b3ce40a 100644
--- a/compiler.c
+++ b/compiler.c
@@ -14,13 +14,13 @@ extern FILE *yyin;
 Stack *stack;
 Node *rootNode;
 
-typedef struct VariableMapValue
+typedef struct IdentifierMapValue
 {
     char *name;
-    LLVMValueRef variable;
-} VariableMapValue;
+    LLVMValueRef value;
+} IdentifierMapValue;
 
-VariableMapValue *namedVariables;
+IdentifierMapValue *namedVariables;
 uint32_t namedVariableCount;
 
 static LLVMValueRef CompileExpression(
@@ -32,11 +32,11 @@ static LLVMValueRef CompileExpression(
 
 static void AddNamedVariable(char *name, LLVMValueRef variable)
 {
-    VariableMapValue mapValue;
+    IdentifierMapValue mapValue;
     mapValue.name = name;
-    mapValue.variable = variable;
+    mapValue.value = variable;
 
-    namedVariables = realloc(namedVariables, namedVariableCount + 1);
+    namedVariables = realloc(namedVariables, sizeof(IdentifierMapValue) * (namedVariableCount + 1));
     namedVariables[namedVariableCount] = mapValue;
 
     namedVariableCount += 1;
@@ -50,7 +50,7 @@ static LLVMValueRef FindVariableByName(char *name)
     {
         if (strcmp(namedVariables[i].name, name) == 0)
         {
-            return namedVariables[i].variable;
+            return namedVariables[i].value;
         }
     }
 
@@ -76,8 +76,7 @@ static LLVMValueRef CompileNumber(
     LLVMBuilderRef builder,
     LLVMValueRef function,
     Node *numberExpression
-)
-{
+) {
     return LLVMConstInt(LLVMInt64Type(), numberExpression->value.number, 0);
 }
 
@@ -94,11 +93,36 @@ static LLVMValueRef CompileBinaryExpression(
     {
         case Add:
             return LLVMBuildAdd(builder, left, right, "tmp");
+
+        case Subtract:
+            return LLVMBuildSub(builder, left, right, "tmp");
+
+        case Multiply:
+            return LLVMBuildMul(builder, left, right, "tmp");
+
     }
 
     return NULL;
 }
 
+static LLVMValueRef CompileFunctionCallExpression(
+    LLVMModuleRef module,
+    LLVMBuilderRef builder,
+    LLVMValueRef function,
+    Node *expression
+) {
+    uint32_t i;
+    uint32_t argumentCount = expression->children[1]->childCount;
+    LLVMValueRef args[argumentCount];
+
+    for (i = 0; i < argumentCount; i += 1)
+    {
+        args[i] = CompileExpression(module, builder, function, expression->children[1]->children[i]);
+    }
+
+    return LLVMBuildCall(builder, FindVariableByName(expression->children[0]->value.string), args, argumentCount, "tmp");
+}
+
 static LLVMValueRef CompileExpression(
     LLVMModuleRef module,
     LLVMBuilderRef builder,
@@ -110,6 +134,9 @@ static LLVMValueRef CompileExpression(
         case BinaryExpression:
             return CompileBinaryExpression(module, builder, function, expression);
 
+        case FunctionCallExpression:
+            return CompileFunctionCallExpression(module, builder, function, expression);
+
         case Identifier:
             return FindVariableByName(expression->value.string);
 
@@ -167,6 +194,8 @@ static void CompileFunction(LLVMModuleRef module, Node *functionDeclaration)
     {
         CompileStatement(module, builder, function, functionBody->children[i]);
     }
+
+    AddNamedVariable(functionSignature->children[0]->value.string, function);
 }
 
 static void Compile(LLVMModuleRef module, Node *node)
diff --git a/stack.c b/stack.c
index 570b1aa..9ab52de 100644
--- a/stack.c
+++ b/stack.c
@@ -10,12 +10,9 @@ Stack* CreateStack()
     stack->stackFrames = (StackFrame*) malloc(sizeof(StackFrame) * stack->stackCapacity);
     for (i = 0; i < stack->stackCapacity; i += 1)
     {
-        stack->stackFrames[i].statements = NULL;
-        stack->stackFrames[i].statementCapacity = 0;
-        stack->stackFrames[i].statementCount = 0;
-        stack->stackFrames[i].declarations = NULL;
-        stack->stackFrames[i].declarationCapacity = 0;
-        stack->stackFrames[i].declarationCount = 0;
+        stack->stackFrames[i].nodes = NULL;
+        stack->stackFrames[i].nodeCapacity = 0;
+        stack->stackFrames[i].nodeCount = 0;
     }
     stack->stackIndex = 0;
     return stack;
@@ -30,12 +27,10 @@ void PushStackFrame(Stack *stack)
         stack->stackCapacity += 1;
         stack->stackFrames = (StackFrame*) realloc(stack->stackFrames, sizeof(StackFrame) * stack->stackCapacity);
 
-        stack->stackFrames[stack->stackIndex].statementCapacity = 0;
-        stack->stackFrames[stack->stackIndex].declarationCapacity = 0;
+        stack->stackFrames[stack->stackIndex].nodeCapacity = 0;
     }
 
-    stack->stackFrames[stack->stackIndex].statementCount = 0;
-    stack->stackFrames[stack->stackIndex].declarationCount = 0;
+    stack->stackFrames[stack->stackIndex].nodeCount = 0;
 }
 
 void PopStackFrame(Stack *stack)
@@ -43,38 +38,20 @@ void PopStackFrame(Stack *stack)
     stack->stackIndex -= 1;
 }
 
-void AddStatement(Stack *stack, Node *statementNode)
+void AddNode(Stack *stack, Node *statementNode)
 {
     StackFrame *stackFrame = &stack->stackFrames[stack->stackIndex];
-    if (stackFrame->statementCount == stackFrame->statementCapacity)
+    if (stackFrame->nodeCount == stackFrame->nodeCapacity)
     {
-        stackFrame->statementCapacity += 1;
-        stackFrame->statements = (Node**) realloc(stackFrame->statements, stackFrame->statementCapacity);
+        stackFrame->nodeCapacity += 1;
+        stackFrame->nodes = (Node**) realloc(stackFrame->nodes, stackFrame->nodeCapacity);
     }
-    stackFrame->statements[stackFrame->statementCount] = statementNode;
-    stackFrame->statementCount += 1;
+    stackFrame->nodes[stackFrame->nodeCount] = statementNode;
+    stackFrame->nodeCount += 1;
 }
 
-Node** GetStatements(Stack *stack, uint32_t *pCount)
+Node** GetNodes(Stack *stack, uint32_t *pCount)
 {
-    *pCount = stack->stackFrames[stack->stackIndex].statementCount;
-    return stack->stackFrames[stack->stackIndex].statements;
-}
-
-void AddDeclaration(Stack *stack, Node *declarationNode)
-{
-    StackFrame *stackFrame = &stack->stackFrames[stack->stackIndex];
-    if (stackFrame->declarationCount == stackFrame->declarationCapacity)
-    {
-        stackFrame->declarationCapacity += 1;
-        stackFrame->declarations = (Node**) realloc(stackFrame->declarations, stackFrame->declarationCapacity);
-    }
-    stackFrame->declarations[stackFrame->declarationCount] = declarationNode;
-    stackFrame->declarationCount += 1;
-}
-
-Node** GetDeclarations(Stack *stack, uint32_t *pCount)
-{
-    *pCount = stack->stackFrames[stack->stackIndex].declarationCount;
-    return stack->stackFrames[stack->stackIndex].declarations;
+    *pCount = stack->stackFrames[stack->stackIndex].nodeCount;
+    return stack->stackFrames[stack->stackIndex].nodes;
 }
diff --git a/stack.h b/stack.h
index 3d118b9..09c8892 100644
--- a/stack.h
+++ b/stack.h
@@ -5,13 +5,9 @@
 
 typedef struct StackFrame
 {
-    Node **statements;
-    uint32_t statementCount;
-    uint32_t statementCapacity;
-
-    Node **declarations;
-    uint32_t declarationCount;
-    uint32_t declarationCapacity;
+    Node **nodes;
+    uint32_t nodeCount;
+    uint32_t nodeCapacity;
 } StackFrame;
 
 typedef struct Stack
@@ -25,9 +21,7 @@ Stack* CreateStack();
 void PushStackFrame(Stack *stack);
 void PopStackFrame(Stack *stack);
 
-void AddStatement(Stack *stack, Node *statementNode);
-Node** GetStatements(Stack *stack, uint32_t *pCount);
-void AddDeclaration(Stack *stack, Node *declarationNode);
-Node** GetDeclarations(Stack *stack, uint32_t *pCount);
+void AddNode(Stack *stack, Node *statementNode);
+Node** GetNodes(Stack *stack, uint32_t *pCount);
 
-#endif /* WRAITH_STACK_H */
\ No newline at end of file
+#endif /* WRAITH_STACK_H */
diff --git a/wraith.lex b/wraith.lex
index 8137c48..056eefc 100644
--- a/wraith.lex
+++ b/wraith.lex
@@ -18,9 +18,9 @@
 \"[a-zA-Z][a-zA-Z0-9]*\"    return STRING_LITERAL;
 "+"                         return PLUS;
 "-"                         return MINUS;
-"*"                         return MULTIPLY;
-"/"                         return DIVIDE;
-"%"                         return MOD;
+"*"                         return STAR;
+"/"                         return SLASH;
+"%"                         return PERCENT;
 "<"                         return LESS_THAN;
 ">"                         return GREATER_THAN;
 "="                         return EQUAL;
diff --git a/wraith.y b/wraith.y
index dee5563..d048896 100644
--- a/wraith.y
+++ b/wraith.y
@@ -34,9 +34,9 @@ extern Node *rootNode;
 %token STRING_LITERAL
 %token PLUS
 %token MINUS
-%token MULTIPLY
-%token DIVIDE
-%token MOD
+%token STAR
+%token SLASH
+%token PERCENT
 %token EQUAL
 %token LESS_THAN
 %token GREATER_THAN
@@ -71,7 +71,7 @@ Program                 : Declarations
                             Node *declarationSequence;
                             uint32_t declarationCount;
 
-                            declarations = GetDeclarations(stack, &declarationCount);
+                            declarations = GetNodes(stack, &declarationCount);
                             declarationSequence = MakeDeclarationSequenceNode(declarations, declarationCount);
 
                             PopStackFrame(stack);
@@ -123,6 +123,7 @@ PrimaryExpression       : Identifier
                         {
                             $$ = $2;
                         }
+                        | FunctionCallExpression
                         ;
 
 UnaryExpression         : BANG Expression
@@ -138,6 +139,10 @@ BinaryExpression        : Expression PLUS Expression
                         {
                             $$ = MakeBinaryNode(Subtract, $1, $3);
                         }
+                        | Expression STAR Expression
+                        {
+                            $$ = MakeBinaryNode(Multiply, $1, $3);
+                        }
 
 Expression              : PrimaryExpression
                         | UnaryExpression
@@ -163,8 +168,20 @@ ReturnStatement         : RETURN Expression
                             $$ = MakeReturnStatementNode($2);
                         }
 
+FunctionCallExpression  : Identifier LEFT_PAREN Arguments RIGHT_PAREN
+                        {
+                            Node **arguments;
+                            uint32_t argumentCount;
+
+                            arguments = GetNodes(stack, &argumentCount);
+                            $$ = MakeFunctionCallExpressionNode($1, MakeFunctionArgumentSequenceNode(arguments, argumentCount));
+
+                            PopStackFrame(stack);
+                        }
+
 PartialStatement        : AssignmentStatement
                         | VariableDeclaration
+                        | FunctionCallExpression
                         | ReturnStatement
                         ;
 
@@ -172,22 +189,36 @@ Statement               : PartialStatement SEMICOLON;
 
 Statements              : Statement Statements
                         {
-                            AddStatement(stack, $1);
+                            AddNode(stack, $1);
                         }
                         |
                         {
                             PushStackFrame(stack);
                         }
 
-Arguments               : VariableDeclaration COMMA VariableDeclarations
+Arguments               : PrimaryExpression COMMA Arguments
                         {
-                            AddDeclaration(stack, $1);
+                            AddNode(stack, $1);
+                        }
+                        | PrimaryExpression
+                        {
+                            PushStackFrame(stack);
+                            AddNode(stack, $1);
+                        }
+                        |
+                        ;
+
+SignatureArguments      : VariableDeclaration COMMA VariableDeclarations
+                        {
+                            AddNode(stack, $1);
                         }
                         | VariableDeclaration
                         {
                             PushStackFrame(stack);
-                            AddDeclaration(stack, $1);
+                            AddNode(stack, $1);
                         }
+                        |
+                        ;
 
 Body                    : LEFT_BRACE Statements RIGHT_BRACE
                         {
@@ -195,19 +226,19 @@ Body                    : LEFT_BRACE Statements RIGHT_BRACE
                             Node *statementSequence;
                             uint32_t statementCount;
 
-                            statements = GetStatements(stack, &statementCount);
+                            statements = GetNodes(stack, &statementCount);
                             statementSequence = MakeStatementSequenceNode(statements, statementCount);
                             $$ = MakeStatementSequenceNode(statements, statementCount);
 
                             PopStackFrame(stack);
                         }
 
-FunctionSignature       : Type Identifier LEFT_PAREN Arguments RIGHT_PAREN
+FunctionSignature       : Type Identifier LEFT_PAREN SignatureArguments RIGHT_PAREN
                         {
                             Node **declarations;
                             uint32_t declarationCount;
 
-                            declarations = GetDeclarations(stack, &declarationCount);
+                            declarations = GetNodes(stack, &declarationCount);
                             $$ = MakeFunctionSignatureNode($2, $1, MakeFunctionSignatureArgumentsNode(declarations, declarationCount));
 
                             PopStackFrame(stack);
@@ -220,7 +251,7 @@ FunctionDeclaration     : FunctionSignature Body
 
 VariableDeclarations    : VariableDeclaration SEMICOLON VariableDeclarations
                         {
-                            AddDeclaration(stack, $1);
+                            AddNode(stack, $1);
                         }
                         |
                         {
@@ -233,7 +264,7 @@ StructDeclaration       : STRUCT Identifier LEFT_BRACE VariableDeclarations RIGH
                             Node *declarationSequence;
                             uint32_t declarationCount;
 
-                            declarations = GetDeclarations(stack, &declarationCount);
+                            declarations = GetNodes(stack, &declarationCount);
                             declarationSequence = MakeDeclarationSequenceNode(declarations, declarationCount);
                             $$ = MakeStructDeclarationNode($2, declarationSequence);
 
@@ -246,7 +277,7 @@ Declaration             : StructDeclaration
 
 Declarations            : Declaration Declarations
                         {
-                            AddDeclaration(stack, $1);
+                            AddNode(stack, $1);
                         }
                         |
                         {