diff --git a/ansible_mitogen/connection.py b/ansible_mitogen/connection.py
index 569a5ad8..4b648d4e 100644
--- a/ansible_mitogen/connection.py
+++ b/ansible_mitogen/connection.py
@@ -64,6 +64,17 @@ def optional_secret(value):
         return mitogen.core.Secret(value)
 
 
+def optional_int(value):
+    """
+    Convert `value` to an integer if it is not :data:`None`, otherwise return
+    :data:`None`.
+    """
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return None
+
+
 def parse_python_path(s):
     """
     Given the string set for ansible_python_interpeter, parse it using shell
@@ -406,7 +417,9 @@ def config_from_play_context(transport, inventory_name, connection):
         'mitogen_machinectl_path':
             connection.get_task_var('mitogen_machinectl_path'),
         'mitogen_ssh_debug_level':
-            connection.get_task_var('mitogen_ssh_debug_level'),
+            optional_int(
+                connection.get_task_var('mitogen_ssh_debug_level')
+            ),
         'extra_args':
             connection.get_extra_args(),
     }
diff --git a/tests/ansible/tests/connection_test.py b/tests/ansible/tests/connection_test.py
new file mode 100644
index 00000000..33b60695
--- /dev/null
+++ b/tests/ansible/tests/connection_test.py
@@ -0,0 +1,38 @@
+
+from __future__ import absolute_import
+import os.path
+import subprocess
+import tempfile
+import unittest2
+
+import mock
+
+import ansible_mitogen.connection
+import testlib
+
+
+LOGGER_NAME = ansible_mitogen.target.LOG.name
+
+
+class OptionalIntTest(unittest2.TestCase):
+    func = staticmethod(ansible_mitogen.connection.optional_int)
+
+    def test_already_int(self):
+        self.assertEquals(0, self.func(0))
+        self.assertEquals(1, self.func(1))
+        self.assertEquals(-1, self.func(-1))
+
+    def test_is_string(self):
+        self.assertEquals(0, self.func("0"))
+        self.assertEquals(1, self.func("1"))
+        self.assertEquals(-1, self.func("-1"))
+
+    def test_is_none(self):
+        self.assertEquals(None, self.func(None))
+
+    def test_is_junk(self):
+        self.assertEquals(None, self.func({1:2}))
+
+
+if __name__ == '__main__':
+    unittest2.main()