diff --git a/CMakeLists.txt b/CMakeLists.txt
index f0089f2a5659070682b15d7290b82ec19a2ea703..f6b422f5bca403145fdc24d03c239e33c26f53ec 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -216,7 +216,7 @@ option(WITH_STRIP       "Strip so files of Whl packages"         OFF)
 
 # PY_VERSION
 if(NOT PY_VERSION)
-  set(PY_VERSION 3.7)
+  set(PY_VERSION 3.6)
 endif()
 set(PYBIND11_PYTHON_VERSION ${PY_VERSION})