diff --git a/pkgs/build-support/fetchdarcs/default.nix b/pkgs/build-support/fetchdarcs/default.nix
index 2644a20d0a53..c28cc35219c5 100644
--- a/pkgs/build-support/fetchdarcs/default.nix
+++ b/pkgs/build-support/fetchdarcs/default.nix
@@ -1,10 +1,13 @@
-{stdenv, darcs, nix}: {url, rev ? null, context ? null, md5 ? "", sha256 ? ""}:
+{stdenv, darcs, nix, cacert}:
+
+{url, rev ? null, context ? null, md5 ? "", sha256 ? ""}:
 
 if md5 != "" then
   throw "fetchdarcs does not support md5 anymore, please use sha256"
 else
 stdenv.mkDerivation {
   name = "fetchdarcs";
+  SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
   builder = ./builder.sh;
   buildInputs = [darcs];