Abstract: A filter press comprises a plurality of membrane filter plates each comprising a base plate and an elastic membrane on at least one side of the base plate. The base plate has a circumferential raised plane edge portion surrounding a recess with a step-form recessed circumferential surface between the raised edge portion and the recess and a groove in the recessed circumferential surface and the raised edge portion. The membrane has a reinforced edge poriton of angular cross section with a first web lying on said recessed circumferential surface of the base plate and having a bevelled edge engaging the shoulder between the recessed circumferential surface and the raised edge portion and a second web received in the groove to provide a seal between the membrane and the base plate. The outer surface of the first web is recessed below the plane of the raised edge portion of the base plate.