They are not both part of NYU.The relationship between these institutions has been changed over the past 2 years and a virtually complete separation is planned soon.(the was a recent NYTimes and Daily News story on this subject.) NYU has a better known name and reputation nationally.. its main hospitals are great teaching hospitals(NYU,NY VA,Bellvue)where most of its clinical education is focused. Mt Sinai is a great institution but farms out its students all over the place sometimes to less than great hospitals.I think either one would give a fine medical education and residency matching is very good for both schools. http://www.nydailynews.com/business/story/95547p-86576c.html