Definitely leather. To be honest, I really don't like the signature bags. Especially those that are the light brown with the dark brown 'C' all over the place, the ones you can see across a store that screams "I'm a COACH bag!!" To each their own (and I don't mean to diss anyone with that bag), but they just bug me for some reason. However, I do own 3 bags that are sig but two of them are the optic green ones that I think are a more muted siggy bag.