OpenSSL/crypto.py           | 3 +++
 OpenSSL/test/test_crypto.py | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/OpenSSL/crypto.py b/OpenSSL/crypto.py
index 555ba24..2c1eddb 100644
--- a/OpenSSL/crypto.py
+++ b/OpenSSL/crypto.py
@@ -464,6 +464,9 @@ class X509Name(object):
         if isinstance(value, _text_type):
             value = value.encode('utf-8')
 
+        # Make it so OpenSSL generates utf-8 strings.
+        _lib.ASN1_STRING_set_default_mask_asc(b'utf8only')
+
         add_result = _lib.X509_NAME_add_entry_by_NID(
             self._name, nid, _lib.MBSTRING_UTF8, value, -1, -1, 0)
         if not add_result:
diff --git a/OpenSSL/test/test_crypto.py b/OpenSSL/test/test_crypto.py
index 1620623..b817451 100644
--- a/OpenSSL/test/test_crypto.py
+++ b/OpenSSL/test/test_crypto.py
@@ -1003,7 +1003,7 @@ class X509NameTests(TestCase):
         self.assertEqual(
             a.der(),
             b('0\x1b1\x0b0\t\x06\x03U\x04\x06\x13\x02US'
-              '1\x0c0\n\x06\x03U\x04\x03\x13\x03foo'))
+              '1\x0c0\n\x06\x03U\x04\x03\x0c\x03foo'))
 
 
     def test_get_components(self):