A facile synthetic pathway to miktoarm star copolymers with multiple arms has been developed by combining reversible addition-fragmentation chain transfer (RAFT) arm-first technique and aldehyde-aminooxy "click" coupling reaction. Star polystyrene (PS) with aldehyde functionalized core was initially prepared by RAFT arm-first technique via crosslinking of the preformed linear macro-RAFT agents using a newly designed aldehyde-containing divinyl compound 6,6'-(ethane-1,2-diylbis(oxy))bis(3-vinylbenzaldehyde) (EVBA). It was then used as a multifunctional coupling agent for the subsequent formation of the second generation poly(ethylene glycol) (PEG) arms via the click coupling reaction between its aldehyde groups and aminooxy-terminated PEGs. The possible formation of PS-PEG miktoarm star copolymer with Janus-like segregated structure in cyclohexanone was also investigated. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3323-3330, 2010