A series of molecularly imprinted polymer nanoparticles have been synthesized employing various template/functional monomer/crosslinking monomer ratio and characterized in detail to elucidate the correlation between the synthetic conditions used and the properties (e.g., particle size and template binding properties) of the obtained nanoparticles. In brief, the presence of propranolol (template) in the polymerization mixture turned out to be a critical factor on determination of the size as well as the binding properties of the imprinted nanoparticles. The functional monomer/crosslinking monomer ratio significantly affects the binding capability of the imprinted nanoparticles, but its influence on the size of the nanoparticles was found to be rather limited. The results obtained provide valuable clues for designing molecularly imprinted nanoparticle preparation in future studies, where fine tuning of particle size and binding properties are required to fit practical applications. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012