My 2.5 month old wore this costume for Halloween last year. The positive was that this costume was absolutely adorable and well made. It is made of a felt-like material, nice and warm. The only downside was that it ran very, very small. It fit my 2.5 month old just fine (12.5 lbs, can't remember what his exact length was but 50th percentile) but would not fit a baby who was ANY bigger than that. So really, I think this should be labelled 0-3 months.