This paper investigates the determinants of knowledge and acceptability of hydrogen vehicles among London residents. Data was collected via a socio-economic survey of over four hundred residents. Results indicate that, at present, less than half of respondents have heard of hydrogen as a fuel for transport, and just over one-third are clearly in favour of the introduction of hydrogen vehicles. The key determinant of acceptability was having prior awareness of hydrogen technologies, as identified via logit regression analysis. Hydrogen awareness in turn was found to be related to gender, age, education and environmental knowledge. These results suggest that there is an opportunity to raise awareness of hydrogen technologies among the remaining three-fifths of the London population, although this is likely to require a differential approach to information provision. (c) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.