diff --git a/gitosis/init.py b/gitosis/init.py
index 61504c8..7ba04cd 100644
--- a/gitosis/init.py
+++ b/gitosis/init.py
@@ -25,7 +25,7 @@ def read_ssh_pubkey(fp=None):
     line = fp.readline()
     return line
 
-_ACCEPTABLE_USER_RE = re.compile(r'^[a-z][a-z0-9]*@[a-z][a-z0-9]*$')
+_ACCEPTABLE_USER_RE = re.compile(r'^[a-z][a-z0-9]*(@[a-z][a-z0-9.-]*)?$')
 
 class InsecureSSHKeyUsername(Exception):
     """Username contains not allowed characters"""
diff --git a/gitosis/test/test_init.py b/gitosis/test/test_init.py
index 8f72b2d..559a0c8 100644
--- a/gitosis/test/test_init.py
+++ b/gitosis/test/test_init.py
@@ -18,6 +18,33 @@ def test_ssh_extract_user_simple():
         +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA= fakeuser@fakehost')
     eq(got, 'fakeuser@fakehost')
 
+def test_ssh_extract_user_domain():
+    got = init.ssh_extract_user(
+        'ssh-somealgo '
+        +'0123456789ABCDEFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA= fakeuser@fakehost.example.com')
+    eq(got, 'fakeuser@fakehost.example.com')
+
+def test_ssh_extract_user_domain_dashes():
+    got = init.ssh_extract_user(
+        'ssh-somealgo '
+        +'0123456789ABCDEFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA= fakeuser@ridiculously-long.example.com')
+    eq(got, 'fakeuser@ridiculously-long.example.com')
+
+def test_ssh_extract_user_no_at():
+    got = init.ssh_extract_user(
+        'ssh-somealgo '
+        +'0123456789ABCDEFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+        +'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA= fakeuser')
+    eq(got, 'fakeuser')
+
 def test_ssh_extract_user_bad():
     e = assert_raises(
         init.InsecureSSHKeyUsername,