Self-perceived psychological stress as a risk factor for coronary artery disease (CAD) was evaluated in a general population study comprising 6,935 men aged 47 to 55 years at baseline without previous myocardial infarction. In 1970 to 1973, the men answered a question about psychological stress defined as a feeling of tension, irritability or anxiety, or as having sleeping difficulties as a result of conditions at work or at home. Psychological stress was graded as follows: (1) never experienced stress; (2) greater than or equal to 1 period of stress; (3) greater than or equal to 1 period of stress during the last 5 years; (4) several periods of stress during the last 5 years; and (5 to 6) permanent stress during the last year or the last 5 years. After a mean follow-up of 11.8 years, 6% of the men with the lowest 4 stress ratings (n = 5,865) had either developed a nonfatal myocardial infarction or died from CAD, with no increase in risk from grade 1 to 4. The corresponding figure among the men with the highest 2 stress ratings (n = 1,070) was 10%; the odds ratio was 1.5 (95% confidence interval 1.2-1.9) after controlling for age and other risk factors. Similar, independent associations were seen with stroke, and with death from cardiovascular disease and from all causes, but not with death from cancer. With respect to CAD, no decrease in the effect of stress at baseline could be seen over time. No relation between life events and self-perceived psychological stress was found in another sample of 732 fifty-year-old men.