Thin-layer molecularly imprinted polymer (MIP) composite membranes for selective binding of monocrotophos (MCP) pesticide from aqueous solutions were developed. The procedure was based on commercially available membrane modules that were rinsed with prepolymerization imprinting mixtures. After the in situ polymerization and generation of MIP films on the membranes within the modules, the membranes were evaluated in terms of affinity toward the target molecule MCP. MIP membranes with different porogens and different monomers on Nylon-6 membranes were prepared. It was shown that MIP membranes synthesized with methacrylic acid as monomer and toluene as porogens on the Nylon-6 membranes provided a highly selective binding of MCP from aqueous solutions under the optimized elution conditions. With the novel surface modification technique, the low nonspecific binding properties of the microfiltration membrane could successfully be combined with the receptor properties of molecular imprints, yielding substance-specific MIP composite membranes. The high affinity of these synthetic membranes to MCP pesticide together with their straightforward and inexpensive preparation could be applied in a fast preconcertration step, solid-phase extraction, by a simple microfitration for the determination of MCP in water. (c) 2006 Wiley Periodicals, Inc.