This paper attempts to compare the research Output and priorities of 25 major Countries in renewable energy research. The main objective is to assess the research priorities of the major countries in frontier areas subjects of renewable energy using some bibliometric measures based on renewable energy literature. Subjects of high activity and Subjects of low activity are identified for two time periods ( 1996-1997 and 1998 1999). Our findings, show that the output of publications including articles. reviews. letters, notes, editorials, and book reviews of India, Greece, and Belgium declined between 1996-1997 and 1998 1999. All measures indicate that in the USA all subjects of renewable energy received more or less the same priority, The rest of the countries had differentiated high- or low-priority profiles in different subjects. Among the main research subjects of renewable energy only photovoltaic technology (PV) had a fairly homogenous profile for all countries. (C) 2002 Elsevier Science Ltd. All rights reserved.