diff --git a/osm2pgsql.nix b/osm2pgsql.nix
index c729ad4..11bdf99 100644
--- a/osm2pgsql.nix
+++ b/osm2pgsql.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
       geos
       libressl    # TLS, crypto implementation
       lua
-      python      # regression tests
+      python python27Packages.psycopg2 # regression tests
       postgresql
       proj
       zlib