diff --git a/pkgs/os-specific/linux/crda/default.nix b/pkgs/os-specific/linux/crda/default.nix
index ac6117cd599..5e63524e7dc 100644
--- a/pkgs/os-specific/linux/crda/default.nix
+++ b/pkgs/os-specific/linux/crda/default.nix
@@ -40,7 +40,13 @@ stdenv.mkDerivation rec {
     longDescription = ''
       CRDA acts as the udev helper for communication between the kernel and
       userspace for regulatory compliance. It relies on nl80211 for communication.
+
       CRDA is intended to be run only through udev communication from the kernel.
+      To use it under NixOS, add
+
+        services.udev.packages = [ pkgs.crda ];
+
+      to the system configuration.
     '';
     homepage = http://drvbp1.linux-foundation.org/~mcgrof/rel-html/crda/;
     license = licenses.free; # "copyleft-next 0.3.0", as yet without a web site