diff --git a/CMakeLists.txt b/CMakeLists.txt
index 60dfb3c8469e57bf38e03a8cee87ca8f3396da18..2657c3044967ddb8da41492ecea0461704c56b54 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -162,7 +162,7 @@ endif ()
 install (TARGETS ${PACKAGE_NAME} DESTINATION ${LIBRARY_INSTALL_DIR} EXPORT gflags-lib)
 install (FILES   ${PUBLIC_HDRS}  DESTINATION ${INCLUDE_INSTALL_DIR}/${GFLAGS_NAMESPACE})
 
-file (RELATIVE_PATH INSTALL_PREFIX_REL2CONFIG_DIR "${CMAKE_INSTALL_PREFIX}" "${CMAKE_INSTALL_PREFIX}/${CONFIG_INSTALL_DIR}")
+file (RELATIVE_PATH INSTALL_PREFIX_REL2CONFIG_DIR "${CMAKE_INSTALL_PREFIX}/${CONFIG_INSTALL_DIR}" "${CMAKE_INSTALL_PREFIX}")
 configure_file (cmake/config.cmake.in  "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-install.cmake" @ONLY)
 configure_file (cmake/version.cmake.in "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-version.cmake" @ONLY)