A review. Mol. imprinting of polymers, a crosslinking polymn. of functional monomers in presence of a template, yields synthetic materials mimicking the function of biol. receptors. The controlled photoinitiated synthesis of thin layers of molecularly imprinted polymers (MIPs) offers many possibilities for development of novel composite materials for affinity technologies. Molecularly imprinted membranes have a very large, but almost unexplored potential for substance-specific sepn., analytics or catalysis. Our aim is the rational design of structure and function of MIP affinity membranes. Our main approach is the controlled functionalization of porous polymeric, esp. microfiltration and track-etched membranes to synthesize novel MIP composite membranes.