diff --git a/pkgs/development/python-modules/generic/default.nix b/pkgs/development/python-modules/generic/default.nix
index 4aa17d28b258..3a6024e09a8b 100644
--- a/pkgs/development/python-modules/generic/default.nix
+++ b/pkgs/development/python-modules/generic/default.nix
@@ -29,6 +29,11 @@
           # move colliding easy_install.pth to specifically named one
           mv "$eapth" $(dirname "$eapth")/${name}.pth
       fi
+
+      # Remove any site.py files generated by easy_install as these
+      # cause collisions. If pth files are to be processed a
+      # corresponding site.py needs to be included in the PYTHONPATH.
+      rm -f "$out/lib/${python.libPrefix}"/site-packages/site.py*
     ''
     
 , buildPhase ? "true"