After reading the reviews, I got a 3T for my chunky toddler who usually wears a 2T.  Glad I did, these definately run small.  They also are cute sort of slim, but sizing up works for us.  These were a good deal (inexpensive) so I plan to get more next winter.  Was really cute looking too.  Also, I liked the softer waist band, I don't like the waist bands on the Old Navy and Gap ones we usually buy.