diff --git a/src/preprocessor.cpp b/src/preprocessor.cpp
index d1dbe6f13..7a01126eb 100644
--- a/src/preprocessor.cpp
+++ b/src/preprocessor.cpp
@@ -467,7 +467,9 @@ std::string Preprocessor::removeSpaceNearNL(const std::string &str)
 std::string Preprocessor::replaceIfDefined(const std::string &str)
 {
     std::string ret(str);
-    std::string::size_type pos = 0;
+    std::string::size_type pos;
+
+    pos = 0;
     while ((pos = ret.find("#if defined(", pos)) != std::string::npos)
     {
         std::string::size_type pos2 = ret.find(")", pos + 9);
@@ -482,6 +484,21 @@ std::string Preprocessor::replaceIfDefined(const std::string &str)
         ++pos;
     }
 
+    pos = 0;
+    while ((pos = ret.find("#if !defined(", pos)) != std::string::npos)
+    {
+        std::string::size_type pos2 = ret.find(")", pos + 9);
+        if (pos2 > ret.length() - 1)
+            break;
+        if (ret[pos2+1] == '\n')
+        {
+            ret.erase(pos2, 1);
+            ret.erase(pos + 3, 10);
+            ret.insert(pos + 3, "ndef ");
+        }
+        ++pos;
+    }
+
     return ret;
 }
 
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index f6d9149a6..e9fd1ce2c 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -93,6 +93,7 @@ private:
         TEST_CASE(multiline4);
 
         TEST_CASE(if_defined);      // "#if defined(AAA)" => "#ifdef AAA"
+        TEST_CASE(if_not_defined);  // "#if !defined(AAA)" => "#ifndef AAA"
 
         // Macros..
         TEST_CASE(macro_simple1);
@@ -591,13 +592,14 @@ private:
     {
         const char filedata[] = "#if defined(AAA)\n"
                                 "#endif\n";
+        ASSERT_EQUALS("#ifdef AAA\n#endif\n", OurPreprocessor::replaceIfDefined(filedata));
+    }
 
-
-        // Expected result..
-        std::string expected("#ifdef AAA\n#endif\n");
-
-        // Compare result..
-        ASSERT_EQUALS(expected, OurPreprocessor::replaceIfDefined(filedata));
+    void if_not_defined()
+    {
+        const char filedata[] = "#if !defined(AAA)\n"
+                                "#endif\n";
+        ASSERT_EQUALS("#ifndef AAA\n#endif\n", OurPreprocessor::replaceIfDefined(filedata));
     }