I can't remember, my kids grew like weeds the first three months and both were in 6-9 by 3 months old. I am hitting some yard sales this morning and need to get my sister's boys some clothes. I can't get a ahold of her to ask what size (phone tag), but I know they are around 12 lbs. So, in real baby sizes, what size for a 12 lb 5 month old?