diff --git a/pykat/finesse.py b/pykat/finesse.py
index 42c0d0635f2cbb56f7bc9490041a14fb5528509a..97e28274bbd1d6b0844e1852e3da44399cca2a08 100644
--- a/pykat/finesse.py
+++ b/pykat/finesse.py
@@ -633,6 +633,9 @@ class kat(object):
         """ Generates the kat file which can then be run """
         
         out = []    
+        import datetime
+        strtoday = datetime.datetime.now()
+        out.append(strtoday.strftime("%% Generated by PyKat %d.%m.%Y %H:%M:%S\n") )
         
         for key in self.__blocks:
             objs = self.__blocks[key].contents