diff --git a/pkgs/by-name/ch/chessdb/package.nix b/pkgs/by-name/ch/chessdb/package.nix
index f17d43c4204d..d9cb6c9dfee7 100644
--- a/pkgs/by-name/ch/chessdb/package.nix
+++ b/pkgs/by-name/ch/chessdb/package.nix
@@ -36,5 +36,6 @@ stdenv.mkDerivation (finalAttrs: {
     homepage = "https://chessdb.sourceforge.net/";
     description = "Free chess database";
     platforms = lib.platforms.linux;
+    license = lib.licenses.gpl2Only;
   };
 })