This foldable chair comprises a frame forming the backrest and the forward prop and being articulately linked to a second frame forming the backward prop and to a plate forming the seat. A characterising feature lies in that the seat is linked in a pin-jointed connection and by means of a link to the second frame, said link having each of its respective ends linked in a pin-jointed connection to the respective one of two pieces being fixedly attached to the lower surface of the seat and to the lower surface of the cross member of the second frame, respectively, the seat coming to rest on this latter cross member.