In a membrane contactor the membrane separation is completely integrated with an extraction or absorption operation in order to exploit the benefits of both technologies fully. Membrane contactor applications that have been developed can be found in both water and gas treatment. Several recently developed applications that have been introduced in industry - selective removal of heavy metals from a galvanic process bath, organic component recovery from a process water in chemical industry and ammonia recovery from an off gas stream - will be discussed technically and economically to show the wide scope of the technology.