diff --git a/pkgs/build-support/builder-defs/builder-defs.nix b/pkgs/build-support/builder-defs/builder-defs.nix
index da5d2249852..42d8f35b076 100644
--- a/pkgs/build-support/builder-defs/builder-defs.nix
+++ b/pkgs/build-support/builder-defs/builder-defs.nix
@@ -23,6 +23,7 @@ let inherit (builtins) head tail trace; in
                 else if hasSuffixHack ".tar.Z" s then "tZ" 
                 else if hasSuffixHack ".tar.lzma" s then "tar.lzma"
                 else if hasSuffixHack ".tar.xz" s then "tar.xz"
+                else if hasSuffixHack ".rar" s then "rar"
                 else if (hasSuffixHack ".zip" s) || (hasSuffixHack ".ZIP" s) then "zip"
                 else if hasSuffixHack "-cvs-export" s then "cvs-dir"
                 else if hasSuffixHack "-git-export" s then "git-dir"
@@ -213,6 +214,9 @@ let inherit (builtins) head tail trace; in
         " else if (archiveType s) == "tar.xz" then "
                 xz -d -c <'${s}' | tar xv
                 cd \"\$(xz -d -c <'${s}' | tar t | head -1 | sed -e 's@/.*@@' )\"
+        " else if (archiveType s) == "rar" then "
+                unrar x '${s}'
+                cd \"$(unrar lb '${s}' | tail -1 | sed -e 's@/.*@@' )\"
         " else if (archiveType s) == "zip" then "
                 unzip '${s}'
                 cd \"$( unzip -lqq '${s}' | tail -1 | 
diff --git a/pkgs/tools/archivers/unrar/default.nix b/pkgs/tools/archivers/unrar/default.nix
index d973649c9ed..eb0d3a3bd83 100644
--- a/pkgs/tools/archivers/unrar/default.nix
+++ b/pkgs/tools/archivers/unrar/default.nix
@@ -23,6 +23,8 @@ stdenv.mkDerivation {
         $out/share/doc/unrar
   '';
 
+  setupHook = ./setup-hook.sh;
+
   meta = with stdenv.lib; {
     description = "Utility for RAR archives";
     homepage = http://www.rarlab.com/;
diff --git a/pkgs/tools/archivers/unrar/setup-hook.sh b/pkgs/tools/archivers/unrar/setup-hook.sh
new file mode 100644
index 00000000000..41d6a5cd217
--- /dev/null
+++ b/pkgs/tools/archivers/unrar/setup-hook.sh
@@ -0,0 +1,5 @@
+unpackCmdHooks+=(_tryUnrar)
+_tryUnrar() {
+    if ! [[ "$curSrc" =~ \.rar$ ]]; then return 1; fi
+    unrar x "$curSrc" >/dev/null
+}