This study constitutes one part of a program for assessing the impact of coal-fired power plants on the surrounding communities. A questionnaire was mailed to a total of 12,000 subjects living in six areas with coal-fired plants and in matched reference areas. The participation rate was 77.3%. In one coal-fired plant/reference area pair, a more detailed medical examination was carried out among subjects who reported symptoms of the respiratory tract. The match between coal-fired plant and reference areas was successful primarily in three pairs. Neither respiratory symptoms nor disease rates were increased among adults or children near any of these plants, but one plant seemed to give rise to annoyance. For the remaining coal-fired plants, consistently higher prevalences of respiratory tract symptoms and annoyance were observed in the surrounding population. The effects cannot, however, conclusively be related to the coal-fired plants. It should be pointed out that the air pollution levels were relatively low, also in the vicinity of most of the plants in this study.