Nanofibrous mats produced by electrospinning are ideal porous substrates for developing chemical systems due to their high specific surface area, large porosity, and enormous structural and chemical tunability. In this work, we report the fabrication of free-standing MOF membranes using electrospun nanofibrous mats as skeletons, and demonstrate the great potential of such nonwoven fiber mats as a new type of porous support in MOF research field. Direct deposition and seeded secondary growth approaches could be used to produce MOF materials within different nanofibrous skeletons, indicating that the developed method of generating MOF membranes has a remarkable flexibility. The characterizations performed show that the resulting products combine the unique properties of both electrospun nanofibers and MOFs, and can be regarded as a new class of hierarchically nanostructured functional materials.