This study tested hypotheses about effects of the Protestant Work Ethic on mental and physical well-being. The Protestant Work Ethic was expected to enhance mental and physical well-being and buffer response to adverse work conditions. Blue collar workers (N = 115) filled out questionnaires. As predicted, workers with high scores on a Protestant Work Ethic scale are more satisfied with their jobs than workers with low scores. General health complaints are partly explained by an interaction between Protestant Work Ethic and Job Richness: when jobs lacked Job Richness, employees with a high Protestant Work Ethic report fewer General Health Complaints than employees with a low Protestant Work Ethic. No interaction effect was found of Protestant Work Ethic for the relationship between Physical Working Conditions and well-being.