Low social class has been identified as a risk factor for coronary heart disease in highly industrialized countries. The authors discuss the social class concept in relation to psychosocial working conditions. Most of those psychosocial work characteristics that are of relevance to cardiovascular risk, namely, skill discretion, authority over decisions, and social support at work, are unevenly distributed across social classes--the lower the social class, the fewer the resources for coping with psychosocial stressors. Furthermore, biomedical risk factors for cardiovascular illness are also unevenly distributed across social class and associated with psychosocial work characteristics. The main conclusion is that part of the association between social class and cardiovascular illness risk may be due to differences in psychosocial work conditions. The psychosocial work conditions may affect the risk through either neuroendocrine mechanisms or lifestyle. Excessive tobacco smoking, for instance, may be enforced by poor working conditions.