Wow! These bibs are the best thing I've ever had on. I just got these in the mail and put them on. They are fantastic! They are like night and day compared to my other shorts. The Chamois is wonderful. It conforms to your body like a second skin. I'm 601 and 185lbs and I got the Medium. I'll say that I have long legs and thin legs at that. But the mediums fit me perfectly. I would agree with other posters that say don't go by the waist size since these are bibs it really doesn't matter. I went to a LBS and tried on similar pairs to get an idea on size and it worked perfectly. I'll be buying at least one more pair very soon so I can wear these all the time if not two pairs. I'm impressed. A must buy.