The purpose of this study was to determine the relationship between the health status and work ability of individuals representing a variety of municipal occupations. In both 1981 and 1985, 4255 employees answered a postal questionnaire. The subjects, aged 44-58 years in 1981, were grouped into physical, mental, or mixed physical and mental job categories. Occupational groups with a high disease prevalence in 1981 had a high, and occupational groups with a low disease prevalence in 1981 a low, disease incidence during the follow-up period. In 1985 every second subject suffered from a musculoskeletal disease. The highest disease prevalence was observed for physically demanding occupations and for men in work with mixed physical and mental demands. Female auxiliary workers, domestic helpers and cooks, and also male installation and transport workers, had the poorest health. The men and women in mental work had the best health and work ability.