diff --git a/docs/changelog.rst b/docs/changelog.rst
index f653d366..9e226f96 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -64,6 +64,9 @@ Mitogen for Ansible
 * `#343 <https://github.com/dw/mitogen/issues/343>`_: the sudo ``--login``
   option is supported.
 
+* `#344 <https://github.com/dw/mitogen/issues/344>`_: connections no longer
+  fail when the parent machine's logged in username contains slashes.
+
 * Runs with many targets executed the module dependency scanner redundantly
   due to missing synchronization, causing significant wasted computation in the
   connection multiplexer subprocess. For one real-world playbook the scanner
@@ -101,6 +104,7 @@ Thanks!
 Mitogen would not be possible without the support of users. A huge thanks for
 the bug reports in this release contributed by
 `Alex Russu <https://github.com/alexrussu>`_,
+`atoom <https://github.com/atoom>`_,
 `Dan Quackenbush <https://github.com/danquack>`_,
 `Jesse London <https://github.com/jesteria>`_,
 `Luca Nunzi <https://github.com/0xlc>`_,
diff --git a/mitogen/parent.py b/mitogen/parent.py
index 14e0ef6d..5ff6ced8 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -93,6 +93,19 @@ def get_core_source():
     return inspect.getsource(mitogen.core)
 
 
+def get_default_remote_name():
+    """
+    Return the default name appearing in argv[0] of remote machines.
+    """
+    s = u'%s@%s:%d'
+    s %= (getpass.getuser(), socket.gethostname(), os.getpid())
+    # In mixed UNIX/Windows environments, the username may contain slashes.
+    return s.translate({
+        ord(u'\\'): ord(u'_'),
+        ord(u'/'): ord(u'_')
+    })
+
+
 def is_immediate_child(msg, stream):
     """
     Handler policy that requires messages to arrive only from immediately
@@ -765,8 +778,7 @@ class Stream(mitogen.core.Stream):
         if connect_timeout:
             self.connect_timeout = connect_timeout
         if remote_name is None:
-            remote_name = '%s@%s:%d'
-            remote_name %= (getpass.getuser(), socket.gethostname(), os.getpid())
+            remote_name = get_default_remote_name()
         if '/' in remote_name or '\\' in remote_name:
             raise ValueError('remote_name= cannot contain slashes')
         self.remote_name = remote_name
diff --git a/tests/parent_test.py b/tests/parent_test.py
index 06eac97e..0b8b5e9a 100644
--- a/tests/parent_test.py
+++ b/tests/parent_test.py
@@ -5,6 +5,7 @@ import sys
 import tempfile
 import time
 
+import mock
 import unittest2
 import testlib
 
@@ -28,6 +29,21 @@ def wait_for_child(pid, timeout=1.0):
     assert False, "wait_for_child() timed out"
 
 
+class GetDefaultRemoteNameTest(testlib.TestCase):
+    func = staticmethod(mitogen.parent.get_default_remote_name)
+
+    @mock.patch('os.getpid')
+    @mock.patch('getpass.getuser')
+    @mock.patch('socket.gethostname')
+    def test_slashes(self, mock_gethostname, mock_getuser, mock_getpid):
+        # Ensure slashes appearing in the remote name are replaced with
+        # underscores.
+        mock_gethostname.return_value = 'box'
+        mock_getuser.return_value = 'ECORP\\Administrator'
+        mock_getpid.return_value = 123
+        self.assertEquals("ECORP_Administrator@box:123", self.func())
+
+
 class ReapChildTest(testlib.RouterMixin, testlib.TestCase):
     def test_connect_timeout(self):
         # Ensure the child process is reaped if the connection times out.