diff --git a/cmake/modules/RootConfiguration.cmake b/cmake/modules/RootConfiguration.cmake
index 24fff9c11a690ab1f69666a6443aa56a6843efa8..fccc9a729981c3c077f7c7240e8911642e82cb18 100644
--- a/cmake/modules/RootConfiguration.cmake
+++ b/cmake/modules/RootConfiguration.cmake
@@ -574,7 +574,7 @@ get_filename_component(altcxx ${CMAKE_CXX_COMPILER} NAME)
 get_filename_component(altf77 "${CMAKE_Fortran_COMPILER}" NAME)
 get_filename_component(altld ${CMAKE_CXX_COMPILER} NAME)
 
-set(pythonvers ${PYTHON_VERSION})
+set(pythonvers ${PYTHON_VERSION_STRING})
 
 #---RConfigure.h---------------------------------------------------------------------------------------------
 configure_file(${PROJECT_SOURCE_DIR}/config/RConfigure.in include/RConfigure.h NEWLINE_STYLE UNIX)