Health-related quality of life was estimated using the physical and mental summary scores of the SF-12 Health Survey in a cross-sectional study of a general population of 23,312 individuals aged 40–47 years in Hordaland County, Norway. The mean scores in the main occupational groups were adjusted for lifestyle factors using a six-way analysis of covariance. The category of legislators, senior officials, and managers scored highest on both the physical and the mental components, whereas the drivers scored lowest on the physical health and agricultural and fishery workers scored lowest on mental health. Smoking showed marked dose-response relationships with reduced physical and mental health, and inverse U-shaped relationships were found for alcohol consumption and the body mass index, with the mental scale for body mass index peaking above the recommended range of 18.5 to 25.0 kg/m2. Although selection bias related to the choice of occupation cannot be ruled out, the low scores of the quality of life measure for the agricultural and fishery workers and the drivers most likely reflect the effect of known health stressors for these occupations.