The first combined use of atom transfer radical polymerization (ATRP) and precipitation polymerization in the molecular imprinting field is described. The utilized polymerization technique, namely atom transfer radical precipitation polymerization (ATRPP), provides MIP microspheres with obvious molecular imprinting effects towards the template, fast template binding kinetics and an appreciable selectivity over structurally related compounds. The living chain propagation mechanism in ATRPP results in MIP spherical particles with diameters (number-average diameter D-n approximate to 3 Inn) much larger than those prepared via traditional radical precipitation polymerization (TRPP). In addition, the MIP microspheres prepared via ATRPP have also proven to show significantly higher high-affinity binding site densities on their surfaces than the MIP generated via TRPP, while the binding association constants K-a and apparent maximum numbers N-max of the high-affinity sites as well as the specific template bindings are almost the same in the two cases. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3257-3270, 2009