Gold nanostars (AuNSs) with tunable morphology were synthesized by a seed-mediated growth method using poly(diallyldimethylammonium chloride) (PDDA) as stabilizer. The number and length of the branches of the nanostars can be controlled by adjusting the amount of silver nitrate. In addition, the AuNSs exhibit an excellent catalytic effect toward the reduction of hydrogen peroxide (H2O2) in deoxygenated phosphate buffer (pH 7.0). Thus, the PDDA-protected AuNSs were utilized to modify glassy carbon electrode directly for fabricating non-enzymatic H2O2 sensor. The fast amperometric response, low detection limit, wide linear range, good selectivity and long-term stability for the electrochemical detection of H2O2 imply a good performance of the AuNSs based sensor. (C) 2013 Elsevier Ltd. All rights reserved.