2 files changed, 9 insertions, 0 deletions
diff --git a/numpy/lib/_iotools.py b/numpy/lib/_iotools.py
index 27143e5c6..b604b8c52 100644
--- a/numpy/lib/_iotools.py
+++ b/numpy/lib/_iotools.py
@@ -205,7 +205,11 @@ class LineSplitter(object):
     #
 
     def __init__(self, delimiter=None, comments='#', autostrip=True, encoding=None):
+        delimiter = _decode_line(delimiter)
+        comments = _decode_line(comments)
+
         self.comments = comments
+
         # Delimiter is a character
         if (delimiter is None) or isinstance(delimiter, basestring):
             delimiter = delimiter or None
diff --git a/numpy/lib/tests/test__iotools.py b/numpy/lib/tests/test__iotools.py
index 5f6c29a4d..b4888f1bd 100644
--- a/numpy/lib/tests/test__iotools.py
+++ b/numpy/lib/tests/test__iotools.py
@@ -53,6 +53,11 @@ class TestLineSplitter(object):
         test = LineSplitter(',')(strg)
         assert_equal(test, ['1', '2', '3', '4', '', '5'])
 
+        # gh-11028 bytes comment/delimiters should get encoded
+        strg = b" 1,2,3,4,,5 % test"
+        test = LineSplitter(delimiter=b',', comments=b'%')(strg)
+        assert_equal(test, ['1', '2', '3', '4', '', '5'])
+
     def test_constant_fixed_width(self):
         "Test LineSplitter w/ fixed-width fields"
         strg = "  1  2  3  4     5   # test"