Title IV of the 1990 Clean Air Act Amendments initiated a dramatic reduction in emissions of sulfur dioxide and nitrogen oxides by electric power plants. This paper presents the results of an integrated assessment of the benefits and costs of the program, using the Tracking and Analysis Framework (TAF) developed for the National Acid Precipitation Assessment Program (NAPAP). Although dramatic uncertainties characterize our estimates especially with respect to the benefits of the program, many of which we have modeled explicitly, we find that the benefits can be expected to substantially outweigh the costs of the emission reductions. The lion's share of benefits result from reduced risk of premature mortality, especially through reduced exposure to sulfates, and these expected benefits measure several times the expected costs of the program. Significant benefits are also estimated for improvements in health morbidity, recreational visibility and residential visibility, each of which measures approximately equal to costs. In contrast, areas that were the focus of attention in the 1980s including effects to soils, forests and aquatic systems still have not been modeled comprehensively, but evidence suggests benefits in these areas to be relatively small, at least with respect to "use values" for the environmental assets that are affected.