A vacuum-assisted suspension device for a lower limb prosthesis secures the prosthesis to a residual body portion. Sandwiched between the residual body portion and an impermeable socket is a flexible liner made of an impermeable material that is porous to allow the transport of air and fluid directly away from the residual body portion to the outer surface of the liner. A fabric distribution layer is located over the liner and between the liner and the socket to allow transmission of such extracted air and fluid laterally over the liner to an evacuation port in the socket. The evacuation port has an associated one-way valve. During use, loading of the socket compresses the flexible liner and air is expelled via the evacuation port. When the load is removed, a vacuum is created directly between the residual body portion and the socket, the vacuum being maintained by the one-way valve.