A survey of fuel cell experts in Japan is used to estimate the time required to develop major elemental technologies required for stationary and automotive applications of polymer electrolyte fuel cells (PEFC). The elemental technologies covered include electrolyte membranes, electrode catalysts, fuel reforming and hydrogen storage, to be applied in next-generation PEFC systems whose operating temperature is 120degreesC or higher. The survey also asks experts to gauge the effect of R&D investment on the time required to develop a technology. Results are analyzed statistically to quantitatively compare success probabilities, time periods and the potential for R&D investment to reduce development time. The estimated net time period needed to reach performance and cost targets for both stationary and automotive PEFC systems averaged around 17 years. In general, the technology for electrolyte membranes is likely to be the most time consuming for R&D, thus accelerating its progress is effective for shortening the total R&D period. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.