[en] The experienced costs of electricity generation by nuclear and conventional plants and the expected costs of future plants are important for evaluating the economic attractiveness of various power projects and for planning the expansion of electrical generating systems. The main objective of this report is to shed some light on recent cost experience, based on well authenticated information made available by the IAEA Member States participating in this study. Cost information was provided by Canada (Ontario Hydro), Czechoslovakia, Hungary, India, the Republic of Korea and Spain. Reference is also made to information received from Brazil, China, France, Russia and the United States of America. The part of the report that deals with cost experience is Section 2, where the costs of both nuclear and fossil fired plants are reviewed. Other sections give emphasis to the analysis of the major issues and relevant cost elements influencing the costs of nuclear power plants and to a discussion of cost projections. Many of the conclusions can also be applied to conventional plants, although they are usually less important than in the case of nuclear plants. 1 ref., figs and tabs