diff --git a/pkgs/osu/default.nix b/pkgs/osu/default.nix
index 12da65bf..d763f21d 100644
--- a/pkgs/osu/default.nix
+++ b/pkgs/osu/default.nix
@@ -32,6 +32,11 @@ stdenv.mkDerivation rec {
       "CXX=mpicxx"
   ];
 
+  env = {
+    MPICH_CC="${stdenv.cc}/bin/${stdenv.cc.targetPrefix}gcc";
+    MPICH_CXX="${stdenv.cc}/bin/${stdenv.cc.targetPrefix}g++";
+  };
+
   postInstall = ''
     mkdir -p $out/bin
     for f in $(find $out -executable -type f); do