diff --git a/pkgs/development/compilers/mono/4.0.nix b/pkgs/development/compilers/mono/4.0.nix
deleted file mode 100644
index 892ae99abaf..00000000000
--- a/pkgs/development/compilers/mono/4.0.nix
+++ /dev/null
@@ -1,9 +0,0 @@
-{ callPackage, Foundation, libobjc }:
-callPackage ./generic.nix (rec {
-  inherit Foundation libobjc;
-  version = "4.0.4.1";
-  sha256 = "1ydw9l89apc9p7xr5mdzy0h97g2q6v243g82mxswfc2rrqhfs4gd";
-  meta = {
-    knownVulnerabilities = [ "CVE-2009-0689" ];
-  };
-})
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index aca3b7fe41f..90fd6cad4c3 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -7243,10 +7243,6 @@ with pkgs;
   mono5 = mono58;
   mono4 = mono48;
 
-  mono40 = lowPrio (callPackage ../development/compilers/mono/4.0.nix {
-    inherit (darwin) libobjc;
-    inherit (darwin.apple_sdk.frameworks) Foundation;
-  });
   mono46 = lowPrio (callPackage ../development/compilers/mono/4.6.nix {
     inherit (darwin) libobjc;
     inherit (darwin.apple_sdk.frameworks) Foundation;