Molecularly imprinted polymers are synthetic materials designed to selectively bind to a templated molecule. In this study, the effect of including both positive and negative charges simultaneously into the hydrogel network on the selective recognition properties of the MIP is examined. Using 3-methacrylamidopropyl trimethylammonium chloride (MAPTAC) as a cationic monomer and 2-acrylamido-2-methylpropane sulfonic acid CAMPS) as an anionic monomer, various ratios of positive to negative charges were tested. Selective recognition properties were dependant on the type of charged monomer that made Lip a majority of the hydrogel's mass. Additionally, polyampholyte MIPs exhibited less swelling than previously studied polyelectrolyte hydrogels. (C) 2009 Elsevier Ltd. All rights reserved.