I dont think its as incredibly rare as some of you guys are making it out to be...I know a couple of people who have done it. Of course, its not as easy as transferring between colleges, and you definitely need a good reason to do it (the most common scenario I've seen...girl marries guy who's a resident/med student at a far away university and transfers to that school). And I think they strongly prefer transfer applicants who apply before the clinical years begin. But again, I wouldnt be surprised if most med schools take 1-2 transfer applicants per year.