up to 6lb, but i have seen on the pampers website that they can be used for a little more than that, a lady said up to 6.5 lb but package says up to 6lp, i think is also on the size of the baby, there some short babys witch they are more spanded in their tummy and legs so it will just fit arround 6 lb. but there is some tall babys that the weight is more in the whole body and that is why they can used them for a longer piriod. my baby was short so he got rid of them a couple of weeks after born.and he was born just a couple of weeks before at 36 weeks, so was not too much diference as a full turm baby.