diff --git a/pypiserver/core.py b/pypiserver/core.py
index 69e71b0..97b7627 100755
--- a/pypiserver/core.py
+++ b/pypiserver/core.py
@@ -204,6 +204,10 @@ The following additional options can be specified with -U:
   -u
     allow updating to unstable version (alpha, beta, rc, dev versions)
 
+  --index-url INDEX_URL
+    use a different pip index url while updating. The default is to use
+    https://pypi.python.org/simple.
+
 Visit http://pypi.python.org/pypi/pypiserver for more information.
 """)
 
@@ -220,6 +224,7 @@ def main(argv=None):
     server = DEFAULT_SERVER
     redirect_to_fallback = True
     fallback_url = "http://pypi.python.org/simple"
+    index_url = "http://pypi.python.org/simple"
     password_file = None
     overwrite = False
 
@@ -230,6 +235,7 @@ def main(argv=None):
     try:
         opts, roots = getopt.getopt(argv[1:], "i:p:r:d:P:Uuxoh", [
             "interface=",
+            "index-url=",
             "passwords=",
             "port=",
             "root=",
@@ -249,6 +255,8 @@ def main(argv=None):
             port = int(v)
         elif k in ("-i", "--interface"):
             host = v
+        elif k == "--index-url":
+            index_url = v
         elif k in ("-r", "--root"):
             roots.append(v)
         elif k == "--disable-fallback":
@@ -288,7 +296,7 @@ def main(argv=None):
     if command == "update":
         packages = frozenset(itertools.chain(*[listdir(r) for r in roots]))
         from pypiserver import manage
-        manage.update(packages, update_directory, update_dry_run, stable_only=update_stable_only)
+        manage.update(packages, update_directory, update_dry_run, stable_only=update_stable_only, index_url=index_url)
         return
 
     a = app(
diff --git a/pypiserver/manage.py b/pypiserver/manage.py
index 6609888..eadb150 100644
--- a/pypiserver/manage.py
+++ b/pypiserver/manage.py
@@ -85,7 +85,7 @@ def build_releases(pkg, versions):
                                replaces=pkg)
 
 
-def find_updates(pkgset, stable_only=True):
+def find_updates(pkgset, stable_only=True, index_url="https://pypi.python.org/pypi/"):
     no_releases = set()
     filter_releases = filter_stable_releases if stable_only else (lambda x: x)
 
@@ -98,7 +98,7 @@ def find_updates(pkgset, stable_only=True):
     sys.stdout.write("checking %s packages for newer version\n" % len(latest_pkgs),)
     need_update = set()
 
-    pypi = make_pypi_client("https://pypi.python.org/pypi/")
+    pypi = make_pypi_client(index_url)
 
     for count, pkg in enumerate(latest_pkgs):
         if count % 40 == 0:
@@ -127,12 +127,12 @@ def find_updates(pkgset, stable_only=True):
     return need_update
 
 
-def update(pkgset, destdir=None, dry_run=False, stable_only=True):
-    need_update = find_updates(pkgset, stable_only=stable_only)
+def update(pkgset, destdir=None, dry_run=False, stable_only=True, index_url="https://pypi.python.org/simple"):
+    need_update = find_updates(pkgset, stable_only=stable_only, index_url=index_url)
     for pkg in sorted(need_update, key=lambda x: x.pkgname):
         sys.stdout.write("# update %s from %s to %s\n" % (pkg.pkgname, pkg.replaces.version, pkg.version))
 
-        cmd = ["pip", "-q", "install", "--no-deps", "-i", "https://pypi.python.org/simple",
+        cmd = ["pip", "-q", "install", "--no-deps", "-i", index_url,
                "-d", destdir or os.path.dirname(pkg.replaces.fn),
                "%s==%s" % (pkg.pkgname, pkg.version)]