diff --git a/gramps/gen/db/read.py b/gramps/gen/db/read.py
index e9fe01f0d..dd2ee2291 100644
--- a/gramps/gen/db/read.py
+++ b/gramps/gen/db/read.py
@@ -102,6 +102,17 @@ DBERRS      = (db.DBRunRecoveryError, db.DBAccessError,
 # Helper functions
 #
 #-------------------------------------------------------------------------  
+def find_byte_surname(key, data):
+    """
+    Creating a surname from raw data of a person, to use for sort and index
+    returns a byte string
+    """
+    surn = __index_surname(data[3][5])
+    # in python 3 we work with unicode internally, but need byte function sometimes
+    if isinstance(surn, UNITYPE):
+        return surn.encode('utf-8')
+    return surn
+
 def find_surname(key, data):
     """
     Creating a surname from raw data of a person, to use for sort and index
diff --git a/gramps/gen/db/write.py b/gramps/gen/db/write.py
index c1f2976c0..0b0eb8882 100644
--- a/gramps/gen/db/write.py
+++ b/gramps/gen/db/write.py
@@ -74,7 +74,7 @@ from ..lib.researcher import Researcher
 from . import (DbBsddbRead, DbWriteBase, BSDDBTxn, 
                     DbTxn, BsddbBaseCursor, BsddbDowngradeError, DbVersionError,
                     DbEnvironmentError, DbUpgradeRequiredError, find_surname,
-                    find_surname_name, DbUndoBSDDB as DbUndo)
+                    find_byte_surname, find_surname_name, DbUndoBSDDB as DbUndo)
 from .dbconst import *
 from ..utils.callback import Callback
 from ..utils.cast import (conv_unicode_tosrtkey, conv_dbstr_to_unicode)
@@ -718,7 +718,7 @@ class DbBsddb(DbBsddbRead, DbWriteBase, UpdateCallback):
         if not self.readonly:
 
             assoc = [
-                (self.person_map, self.surnames,  find_surname),
+                (self.person_map, self.surnames,  find_byte_surname),
                 (self.person_map, self.id_trans,  find_idmap),
                 (self.family_map, self.fid_trans, find_idmap),
                 (self.event_map,  self.eid_trans, find_idmap),