With the purpose of enhancing the reaction rate of the nitroxide-mediated radical polymerization (NMRP) of styrene in the presence of TEMPO (2,2,6,6-tetramethyl-l-piperidinyloxy), while maintaining the livingness of the system, the effect of the use of a di-functional initiator was investigated. Dibenzoyl peroxide (BPO) and tert-butylperoxy-2-ethylhexyl carbonate (TBEC) were applied as mono-functional initiators and 1, 1-di(tert-amylperoxy)-cyclohexane (Luperox L531) as di-functional initiator. It was shown that in the case of the di-functional initiator, the polymerization rate and the number average molecular weight could be simultaneously increased relative to the performance observed with the mono-functional initiators, under the reaction conditions. (c) 2007 Elsevier Ltd. All rights reserved.