diff --git a/changelog/214.bugfix b/changelog/214.bugfix
new file mode 100644
index 00000000..8a5d7586
--- /dev/null
+++ b/changelog/214.bugfix
@@ -0,0 +1 @@
+Fix crash when transferring internal pytest warnings from workers to the master node.
diff --git a/testing/acceptance_test.py b/testing/acceptance_test.py
index bc71b8ce..b1d3428f 100644
--- a/testing/acceptance_test.py
+++ b/testing/acceptance_test.py
@@ -340,18 +340,28 @@ def test_func():
         ])
 
     @pytest.mark.parametrize('n', ['-n0', '-n1'])
-    def test_logwarning(self, testdir, n):
+    @pytest.mark.parametrize('warn_type', ['pytest', 'builtin'])
+    def test_logwarning(self, testdir, n, warn_type):
         from pkg_resources import parse_version
         if parse_version(pytest.__version__) < parse_version('3.1'):
             pytest.skip('pytest warnings requires >= 3.1')
+
+        if warn_type == 'builtin':
+            warn_code = """warnings.warn(UserWarning('this is a warning'))"""
+        elif warn_type == 'pytest':
+            warn_code = """request.config.warn('', 'this is a warning',
+                           fslocation=py.path.local())"""
+        else:
+            assert False
         testdir.makepyfile("""
-            import warnings
-            def test_func():
-                warnings.warn('this is a warning')
-        """)
+            import warnings, py
+            def test_func(request):
+                {warn_code}
+        """.format(warn_code=warn_code))
         result = testdir.runpytest(n)
         result.stdout.fnmatch_lines([
             "*this is a warning*",
+            "*1 passed, 1 warnings*",
         ])
 
 
diff --git a/xdist/remote.py b/xdist/remote.py
index f9760602..791da787 100644
--- a/xdist/remote.py
+++ b/xdist/remote.py
@@ -99,7 +99,7 @@ def pytest_collectreport(self, report):
 
     def pytest_logwarning(self, message, code, nodeid, fslocation):
         self.sendevent("logwarning", message=message, code=code, nodeid=nodeid,
-                       fslocation=fslocation)
+                       fslocation=str(fslocation))
 
 
 def serialize_report(rep):