The present invention is directed to a process for forming star shaped microgels which include a core of crosslinked polymer and multiplicity of substantially linear polymeric arms of macromonomers attached to the core. The process includes polymerizing monoethylenically unsaturated monomers in the presence of a chain transfer agent to form macromonomers each having a terminal polymerizable ethylenically unsaturated group and then polymerizing, in presence of the macromonomers, the monoethylenically unsaturated monomers and multi-olefinic crosslinking monomers. The microgels of the present invention can be used as rheology control agents in waterborne and solvent-borne coatings and in adhesives and cosmetics.