diff --git a/pkgs/games/atanks/default.nix b/pkgs/games/atanks/default.nix
index 05b645ee326..de9eb9bbb58 100644
--- a/pkgs/games/atanks/default.nix
+++ b/pkgs/games/atanks/default.nix
@@ -18,5 +18,6 @@ stdenv.mkDerivation rec {
     homepage = http://atanks.sourceforge.net/;
     maintainers = [ maintainers.raskin ];
     platforms = platforms.linux;
+    license = licenses.gpl2;
   };
 }