diff --git a/src/CBot/CBotInstr/CBotExprLitNum.cpp b/src/CBot/CBotInstr/CBotExprLitNum.cpp
index 9842cf57..61978bf0 100644
--- a/src/CBot/CBotInstr/CBotExprLitNum.cpp
+++ b/src/CBot/CBotInstr/CBotExprLitNum.cpp
@@ -114,6 +114,46 @@ CBotInstr* CompileExprLitNum(CBotToken* &p, CBotCStack* pStack)
     return pStack->Return(nullptr, pStk);
 }
 
+CBotInstr* CompileSizeOf(CBotToken* &p, CBotCStack* pStack)
+{
+    CBotToken* pp = p;
+
+    if (!IsOfType(p, TokenTypVar)) return nullptr;
+    if (pp->GetString() == "sizeof" && IsOfType(p, ID_OPENPAR))
+    {
+        CBotCStack* pStk = pStack->TokenStack();
+
+        int value;
+
+        if (IsOfType(p, ID_BYTE)) value = sizeof(signed char);
+        else if (IsOfType(p, ID_SHORT)) value = sizeof(short);
+        else if (IsOfType(p, ID_CHAR)) value = sizeof(uint32_t);
+        else if (IsOfType(p, ID_INT)) value = sizeof(int);
+        else if (IsOfType(p, ID_LONG)) value = sizeof(long);
+        else if (IsOfType(p, ID_FLOAT)) value = sizeof(float);
+        else if (IsOfType(p, ID_DOUBLE)) value = sizeof(double);
+        else
+        {
+            p = pp;
+            return pStack->Return(nullptr, pStk);
+        }
+
+        if (IsOfType(p, ID_CLOSEPAR))
+        {
+            auto inst = new CBotExprLitNum<int>(value);
+            inst->SetToken(pp);
+
+            CBotVar* var = CBotVar::Create("", CBotTypInt);
+            pStk->SetVar(var);
+            return pStack->Return(inst, pStk);
+        }
+        pStk->SetError(CBotErrClosePar, p->GetStart());
+        return pStack->Return(nullptr, pStk);
+    }
+    p = pp;
+    return nullptr;
+}
+
 template <typename T>
 bool CBotExprLitNum<T>::Execute(CBotStack* &pj)
 {
diff --git a/src/CBot/CBotInstr/CBotExprLitNum.h b/src/CBot/CBotInstr/CBotExprLitNum.h
index 92cd302d..8d7edcc1 100644
--- a/src/CBot/CBotInstr/CBotExprLitNum.h
+++ b/src/CBot/CBotInstr/CBotExprLitNum.h
@@ -26,6 +26,8 @@ namespace CBot
 
 CBotInstr* CompileExprLitNum(CBotToken* &p, CBotCStack* pStack);
 
+CBotInstr* CompileSizeOf(CBotToken* &p, CBotCStack* pStack);
+
 /**
  * \brief A number literal - 5, 1, 2.5, 3.75, etc. or a predefined numerical constant (see CBotToken::DefineNum())
  *
diff --git a/src/CBot/CBotInstr/CBotParExpr.cpp b/src/CBot/CBotInstr/CBotParExpr.cpp
index 24bdaafe..9572ff5e 100644
--- a/src/CBot/CBotInstr/CBotParExpr.cpp
+++ b/src/CBot/CBotInstr/CBotParExpr.cpp
@@ -68,6 +68,13 @@ CBotInstr* CBotParExpr::Compile(CBotToken* &p, CBotCStack* pStack)
     if (inst != nullptr || !pStk->IsOk())
         return pStack->Return(inst, pStk);
 
+    // is it sizeof operator ?
+    inst = CBot::CompileSizeOf(p, pStk);
+    if (inst != nullptr || !pStk->IsOk())
+    {
+        return pStack->Return(inst, pStk);
+    }
+
     // is it a variable name?
     if (p->GetType() == TokenTypVar)
     {
@@ -155,6 +162,13 @@ CBotInstr* CBotParExpr::CompileLitExpr(CBotToken* &p, CBotCStack* pStack)
         return pStack->Return(inst, pStk);
     }
 
+    // is it sizeof operator ?
+    inst = CBot::CompileSizeOf(p, pStk);
+    if (inst != nullptr || !pStk->IsOk())
+    {
+        return pStack->Return(inst, pStk);
+    }
+
     // is this a chaine?
     if (p->GetType() == TokenTypString)
     {