diff --git a/pkgs/build-support/fetchgit/builder.sh b/pkgs/build-support/fetchgit/builder.sh
new file mode 100644
index 00000000000..08a1cc5d341
--- /dev/null
+++ b/pkgs/build-support/fetchgit/builder.sh
@@ -0,0 +1,13 @@
+source $stdenv/setup
+
+header "exporting $url (rev $rev) into $out"
+
+git clone "$url" $out
+if test -n "$rev"; then
+  cd $out
+  git checkout $rev
+fi
+find $out -name .git\* | xargs rm -rf
+
+stopNest
+
diff --git a/pkgs/build-support/fetchgit/default.nix b/pkgs/build-support/fetchgit/default.nix
new file mode 100644
index 00000000000..3193057f321
--- /dev/null
+++ b/pkgs/build-support/fetchgit/default.nix
@@ -0,0 +1,23 @@
+{stdenv, git}:
+{url, rev ? "HEAD", md5 ? "", sha256 ? ""}:
+
+stdenv.mkDerivation {
+  name = "git-export";
+  builder = ./builder.sh;
+  buildInputs = [git];
+
+  outputHashAlgo = if sha256 == "" then "md5" else "sha256";
+  outputHashMode = "recursive";
+  outputHash = if sha256 == "" then md5 else sha256;
+
+  inherit url rev ;
+
+  impureEnvVars = [
+    # We borrow these environment variables from the caller to allow
+    # easy proxy configuration.  This is impure, but a fixed-output
+    # derivation like fetchurl is allowed to do so since its result is
+    # by definition pure.
+    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
+    ];
+}
+
diff --git a/pkgs/build-support/fetchgit/nix-prefetch-git b/pkgs/build-support/fetchgit/nix-prefetch-git
new file mode 100755
index 00000000000..6e88b1d9c2f
--- /dev/null
+++ b/pkgs/build-support/fetchgit/nix-prefetch-git
@@ -0,0 +1,66 @@
+#! /bin/sh -e
+
+url=$1
+rev=$2
+expHash=$3
+
+hashType=$NIX_HASH_ALGO
+if test -z "$hashType"; then
+    hashType=md5
+fi
+
+if test -z "$url"; then
+    echo "syntax: nix-prefetch-git URL [REVISION [EXPECTED-HASH]]" >&2
+    exit 1
+fi
+
+# If the hash was given, a file with that hash may already be in the
+# store.
+if test -n "$expHash"; then
+    finalPath=$(nix-store --print-fixed-path --recursive "$hashType" "$expHash" git-export)
+    if ! nix-store --check-validity "$finalPath" 2> /dev/null; then
+        finalPath=
+    fi
+    hash=$expHash
+fi
+
+
+# If we don't know the hash or a path with that hash doesn't exist,
+# download the file and add it to the store.
+if test -z "$finalPath"; then
+
+    tmpPath=/tmp/git-checkout-tmp-$$
+    tmpFile=$tmpPath/git-export
+    mkdir $tmpPath
+
+    trap "rm -rf $tmpPath" EXIT
+
+    # Perform the checkout.
+    git clone "$url" $tmpFile
+    if test -n "$rev"; then
+      cd $tmpFile
+      echo $tmpFile
+      git checkout $rev
+    fi
+    find $tmpFile -name .git\* | xargs rm -rf
+
+    # Compute the hash.
+    hash=$(nix-hash --type $hashType $hashFormat $tmpFile)
+    if ! test -n "$QUIET"; then echo "hash is $hash" >&2; fi
+
+    # Add the downloaded file to the Nix store.
+    finalPath=$(nix-store --add-fixed --recursive "$hashType" $tmpFile)
+
+    if test -n "$expHash" -a "$expHash" != "$hash"; then
+        echo "hash mismatch for URL \`$url'"
+        exit 1
+    fi
+fi
+
+if ! test -n "$QUIET"; then echo "path is $finalPath" >&2; fi
+
+echo $hash
+
+if test -n "$PRINT_PATH"; then
+    echo $finalPath
+fi
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 4fe40b6d6b4..5eed302be69 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -252,6 +252,10 @@ let
     inherit stdenv darcs nix;
   };
 
+  fetchgit = import ../build-support/fetchgit {
+    inherit stdenv git;
+  };
+
   fetchsvn = import ../build-support/fetchsvn {
     inherit stdenv subversion openssh;
     sshSupport = true;