diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7be33d1221..595622d40a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -213,7 +213,7 @@ else()
   set(OPENCV_DEBUG_POSTFIX "")
 endif()
 
-if(NOT "${CMAKE_DEBUG_POSTFIX}" STREQUAL "")
+if(DEFINED CMAKE_DEBUG_POSTFIX)
   set(OPENCV_DEBUG_POSTFIX "${CMAKE_DEBUG_POSTFIX}")
 endif()