In this study, the Taguchi method was applied to determine optimum structural combination of a membrane electrode assembly (MEA) in obtaining maximum power density of a PEMFC. Performance measure analysis was also followed by performing a variance analysis, in order to determine the optimum levels and relative magnitude of the effect of combinations. The optimum structural combinations of MEA were found to be membrane, Nafion 112 with a thickness of 51 mu m, amount of platinum loaded by sputtering, 0.05 mg Pt cm(-2), Nafion ionomer content, 0.05 mg cm(-2) and support material of gas diffusion layer (GDL), carbon paper. Under these conditions, the amount of maximum power density was predicted as 563.75 mW cm(-2) by using experimental results obtained according to Taguchi's orthogonal array (OA) L-16(2(4) x 2(2)). Verification experiment was done for the same optimum structural combination and maximum power density was observed as 566 mW cm(-2). According to the results of this optimization, it was seen that amount of platinum loaded by sputtering and thickness of membrane were the effective parameters. (C) 2008 Elsevier B.V. All rights reserved.