diff --git a/builtin-pack-refs.c b/builtin-pack-refs.c
index 0fc8a555e7..246dd6372e 100644
--- a/builtin-pack-refs.c
+++ b/builtin-pack-refs.c
@@ -2,6 +2,20 @@
 #include "refs.h"
 
 static const char *result_path, *lock_path;
+static const char builtin_pack_refs_usage[] =
+"git-pack-refs [--prune]";
+
+struct ref_to_prune {
+	struct ref_to_prune *next;
+	unsigned char sha1[20];
+	char name[FLEX_ARRAY];
+};
+
+struct pack_refs_cb_data {
+	int prune;
+	struct ref_to_prune *ref_to_prune;
+	FILE *refs_file;
+};
 
 static void remove_lock_file(void)
 {
@@ -9,21 +23,70 @@ static void remove_lock_file(void)
 		unlink(lock_path);
 }
 
+static int do_not_prune(int flags)
+{
+	/* If it is already packed or if it is a symref,
+	 * do not prune it.
+	 */
+	return (flags & (REF_ISSYMREF|REF_ISPACKED));
+}
+
 static int handle_one_ref(const char *path, const unsigned char *sha1,
 			  int flags, void *cb_data)
 {
-	FILE *refs_file = cb_data;
+	struct pack_refs_cb_data *cb = cb_data;
 
 	/* Do not pack the symbolic refs */
 	if (!(flags & REF_ISSYMREF))
-		fprintf(refs_file, "%s %s\n", sha1_to_hex(sha1), path);
+		fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
+	if (cb->prune && !do_not_prune(flags)) {
+		int namelen = strlen(path) + 1;
+		struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
+		hashcpy(n->sha1, sha1);
+		strcpy(n->name, path);
+		n->next = cb->ref_to_prune;
+		cb->ref_to_prune = n;
+	}
 	return 0;
 }
 
+/* make sure nobody touched the ref, and unlink */
+static void prune_ref(struct ref_to_prune *r)
+{
+	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1, 1);
+
+	if (lock) {
+		unlink(git_path(r->name));
+		unlock_ref(lock);
+	}
+}
+
+static void prune_refs(struct ref_to_prune *r)
+{
+	while (r) {
+		prune_ref(r);
+		r = r->next;
+	}
+}
+
 int cmd_pack_refs(int argc, const char **argv, const char *prefix)
 {
-	int fd;
-	FILE *refs_file;
+	int fd, i;
+	struct pack_refs_cb_data cbdata;
+
+	memset(&cbdata, 0, sizeof(cbdata));
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+		if (!strcmp(arg, "--prune")) {
+			cbdata.prune = 1;
+			continue;
+		}
+		/* perhaps other parameters later... */
+		break;
+	}
+	if (i != argc)
+		usage(builtin_pack_refs_usage);
 
 	result_path = xstrdup(git_path("packed-refs"));
 	lock_path = xstrdup(mkpath("%s.lock", result_path));
@@ -33,14 +96,17 @@ int cmd_pack_refs(int argc, const char **argv, const char *prefix)
 		die("unable to create new ref-pack file (%s)", strerror(errno));
 	atexit(remove_lock_file);
 
-	refs_file = fdopen(fd, "w");
-	if (!refs_file)
-		die("unable to create ref-pack file structure (%s)", strerror(errno));
-	for_each_ref(handle_one_ref, refs_file);
+	cbdata.refs_file = fdopen(fd, "w");
+	if (!cbdata.refs_file)
+		die("unable to create ref-pack file structure (%s)",
+		    strerror(errno));
+	for_each_ref(handle_one_ref, &cbdata);
 	fsync(fd);
-	fclose(refs_file);
+	fclose(cbdata.refs_file);
 	if (rename(lock_path, result_path) < 0)
 		die("unable to overwrite old ref-pack file (%s)", strerror(errno));
 	lock_path = NULL;
+	if (cbdata.prune)
+		prune_refs(cbdata.ref_to_prune);
 	return 0;
 }