diff --git a/debian/rules b/debian/rules
index f5b71eb..a96c893 100755
--- a/debian/rules
+++ b/debian/rules
@@ -50,6 +50,7 @@
 	$(RM) -r doc/core/
 	$(RM) -r doc/ctrl/
 	$(RM) -r doc/gsm/
+	$(RM) -r doc/isdn/
 	$(RM) -r doc/gb/
 	$(RM) -r doc/vty/html/
 	$(RM) -r doc/vty/latex/