Psychological job stress in the American workplace was reviewed. Claims of stress as a cause of physical disability increased dramatically since 1983, but occupational stress has remained nebulous with numerous events and processes being involved. A brief historical background of job stress was provided, with discussion of its emotional, psychosomatic, hormonal, and cardiovascular impact. The recognition of these factors was manifest in NIOSH and OSHA sponsored studies, and the regulatory laws enacted. A model of job stress and health relationships was developed which took into account job stressors and their consequences. In general, job stressors fell into three categories: job/task demands, organizational factors, and physical conditions. Examples of common stressors in each category were described. Moderating factors were personal and situational characteristics that altered or modified the way individual workers perceived or reacted to the work situation. Extraoccupational factors acknowledged the potential for interaction of home and the workplace. Buffer factors such as social support, coping responses, and lifestyle factors were discussed. Job stress reduction included stress management programs, and organizational changes, which had to be generic and effective. Relationships between job stress and immune system responses were discussed using data from both animal and human research. Work force trends indicated an increase in jobs with only limited opportunities for growth, and an elevation in risks of psychological disorders was expected. Surveillance of psychological risk factors in various occupations, and interventions to reduce job stress were discussed. They were expected to remain a high priority through the 1990s. Methodologic needs in assessing job stress were outlined. The authors conclude that the human and organizational costs of stress cannot be ignored.