Drawing on recent theoretical developments in cognitive and social psychology, self-control demands were introduced as a new source of stress at work. Affective organisational commitment was expected to operate as a buffer in the relation between self-control demands and indicators of job strain. Data provided by 260 nurses in homes for elderly people revealed both significant relationships of self-control demands and commitment to a broad spectrum of strain indicators that included not only self-report measures (burnout, psychosomatic complaints, intentions of quitting), but also a measure of absenteeism. Self-control demands were positively related to all indicators of job strain, whereas the associations were negative for affective commitment. In addition, the results provided clear evidence for the buffer hypothesis of commitment. The positive relations of high self-control demands to all strain indicators were attenuated as a function of affective commitment. The results suggest that the buffer effect of commitment is mainly due to stress-contingent appraisal processes rendering highly committed employees less vulnerable to the adverse effects of high stress.