Star-branched polystyrenes, with polydispersity indices of 1.15-1.56 and 4-644 equal arms, were synthesized by the reaction of 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO)-capped polystyrene (PS-T) with divinylbenzene (DVB). The characterization of PS-T and the final star polymers was carried out by size exclusion chromatography, low-angle laser light scattering, and viscometry. The degree of branching of the star polymers depended on the DVB/PS-T ratio and the PS-T molecular weight. An asymmetric (or miktoarm) star homopolymer of the PS,PS', type was made by the reaction of the PS, symmetric star, which had n TEMPO molecules on its nucleus and consisted of a multifunctional initiator, with extra styrene. (C) 2000 John Wiley & Sons, Inc.