We report a simple preparation of three-armed (A(3)-type) star polymers based on the arm-first technique, using a click-reaction strategy between a well-defined azide-end-functionalized polystyrene, poly(tert-butyl acrylate), or poly(ethylene glycol) precursor and a trisalkyne-functional initiator, 1,1,1-tris[4-(2-propynyloxy)phenyllethane. The click-reaction efficiency for A(3)-type star formation has been investigated with gel permeation chromatography measurements (refractive-index detector). The gel permeation chromatography curves have been split with the deconvolution method (Gaussian area), and the efficiency of A(3)-type star formation has been found to be 87%. (c) 2006 Wiley Periodicals, Inc.