diff --git a/src/calibre/ebooks/fb2/fb2ml.py b/src/calibre/ebooks/fb2/fb2ml.py
index d57389445c..fb3c7f34f7 100644
--- a/src/calibre/ebooks/fb2/fb2ml.py
+++ b/src/calibre/ebooks/fb2/fb2ml.py
@@ -91,7 +91,7 @@ class FB2MLizer(object):
         return u'<?xml version="1.0" encoding="UTF-8"?>\n%s' % etree.tostring(etree.fromstring(output), encoding=unicode, pretty_print=True)
 
     def clean_text(self, text):
-        text = re.sub('<p>\s*</p>', '', text)
+        text = re.sub(r'<p>\s*</p>', '', text)
 
         return text