Abstract: A porous structure comprising a macroporous support and a microporous membrane adhered to the outside surface of the support. Each of the support and membrane may be formed of a synthetic polymer, the polymers of the support and membrane usually being different from each other. The structure is formed by placing the membrane and a quantity of heat-fusible particles in contact with each other, and subjecting the membrane and particles to heat and pressure to fuse the particles into a macroporous support. The melting point of the membrane material should be no lower than that of the particle material.