Russ, I think you'd be better off parsing the compiled data, it's a lot more consistent. Thanks, =Billy Bennett ________________________________ From: russ [mailto:russell.sayers@gmail.com] Sent: Saturday, June 06, 2009 11:53 PM To: tz@lecserver.nci.nih.gov Subject: tz file format Hi, I hope i'm not wasting your time. I'm attempting to read the tz database into a c# application, and I'm not sure how to interpret this entry: Zone Australia/Hobart 9:49:16 - LMT 1895 Sep 10:00 - EST 1916 Oct 1 2:00 10:00 1:00 EST 1917 Feb 10:00 Aus EST 1967 10:00 AT EST What is the significance of the "1:00" on the row ending in "1917 Feb". Do I just add this to the 10:00 offset? Thanks, Russell