An acrylic resin imprinted with a transition state analogue which possesses a dominant non-polar structure was synthesized. As a model for this study the Diels-Alder reaction was chosen since, it is well-known and possesses a stable and synthetically achievable transition state analogue. It is shown that the plastic antibody synthesized in this study catalyzes the Diels-Alder reaction with an efficiency comparable to that of a recently developed monoclonal catalytic antibody. In fact the Lineweaver-Burk V-max observed for the two catalysts appears to be of the same order of magnitude. We argue that plastic antibodies can be successfully used to catalyze reactions with a transition state of low polarity. Moreover, they appear to represent a more flexible catalyst when varied reaction conditions and solvent environments are needed. (C) 2004 Elsevier B.V. All rights reserved.