diff --git a/hgext/releasenotes.py b/hgext/releasenotes.py
--- a/hgext/releasenotes.py
+++ b/hgext/releasenotes.py
@@ -99,6 +99,10 @@
 
         This is used to combine multiple sources of release notes together.
         """
+        if not fuzz:
+            ui.warn(_("module 'fuzzywuzzy' not found, merging of similar"
+                      " releasenotes is disbaled"))
+
         for section in other:
             existingnotes = converttitled(self.titledforsection(section)) + \
                 convertnontitled(self.nontitledforsection(section))