diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4d059a2e6..69572192f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -259,8 +259,11 @@ if (NOT (WIN32 OR CYGWIN))
 else (NOT (WIN32 OR CYGWIN))
   option (BUILD_SHARED_LIBS "Build shared libraries." OFF)
 endif (NOT (WIN32 OR CYGWIN))
+
 if (BUILD_SHARED_LIBS AND (WIN32 OR CYGWIN))
-  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+  if (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
+    set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+  endif (NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
 endif(BUILD_SHARED_LIBS AND (WIN32 OR CYGWIN))
 
 option (BUILD_SOURCE_DOCUMENTATION "Build source documentation with Doxygen." OFF)