diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 90f61662a20e..cf4e0f24e11b 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -165,15 +165,16 @@ def _num_to_str(val):
 def _nums_to_str(*args):
     return ' '.join(map(_num_to_str,args))
 
+
 def quote_ps_string(s):
     "Quote dangerous characters of S for use in a PostScript string constant."
-    s=s.replace("\\", "\\\\")
-    s=s.replace("(", "\\(")
-    s=s.replace(")", "\\)")
-    s=s.replace("'", "\\251")
-    s=s.replace("`", "\\301")
-    s=re.sub(r"[^ -~\n]", lambda x: r"\%03o"%ord(x.group()), s)
-    return s
+    s = s.replace(b"\\", b"\\\\")
+    s = s.replace(b"(", b"\\(")
+    s = s.replace(b")", b"\\)")
+    s = s.replace(b"'", b"\\251")
+    s = s.replace(b"`", b"\\301")
+    s = re.sub(br"[^ -~\n]", lambda x: br"\%03o" % ord(x.group()), s)
+    return s.decode('ascii')
 
 
 def seq_allequal(seq1, seq2):