diff --git a/git/cmd.py b/git/cmd.py
index 2f900ae20..7bd94e4d9 100644
--- a/git/cmd.py
+++ b/git/cmd.py
@@ -355,7 +355,7 @@ def __init__(self, size, stream):
         def read(self, size=-1):
             bytes_left = self._size - self._nbr
             if bytes_left == 0:
-                return ''
+                return b''
             if size > -1:
                 # assure we don't try to read past our limit
                 size = min(bytes_left, size)
@@ -374,7 +374,7 @@ def read(self, size=-1):
 
         def readline(self, size=-1):
             if self._nbr == self._size:
-                return ''
+                return b''
 
             # clamp size to lowest allowed value
             bytes_left = self._size - self._nbr
diff --git a/git/test/test_repo.py b/git/test/test_repo.py
index 5035cbb9f..177aa1767 100644
--- a/git/test/test_repo.py
+++ b/git/test/test_repo.py
@@ -454,7 +454,7 @@ def mktiny():
         assert s.readline() == l1
         assert s.readline() == l2
         assert s.readline() == l3
-        assert s.readline() == ''
+        assert s.readline() == b''
         assert s._stream.tell() == len(d)
 
         # readline limit
@@ -465,13 +465,13 @@ def mktiny():
         # readline on tiny section
         s = mktiny()
         assert s.readline() == l1p
-        assert s.readline() == ''
+        assert s.readline() == b''
         assert s._stream.tell() == ts + 1
 
         # read no limit
         s = mkfull()
         assert s.read() == d[:-1]
-        assert s.read() == ''
+        assert s.read() == b''
         assert s._stream.tell() == len(d)
 
         # read limit