PIP: The case histories of all ischemic nonembolic cerebrovascular disease patients under 50 years old seen at the Department of Neurology of the University of Helsinki during 1966-71 were analyzed. The response rate to a detailed questionnaire was very high. 128 men and 85 women comprised the patient population. Cigarette smoking, oral contraceptive use, hypertension, and electrocardiographic abnormalities appeared to be associated with increased risk of cerebrovascular disease. The role played by obesity remained unclear. 78 women provided detailed information about personal oral contraceptive use. 30% of these women and 39% of the 52 women of childbearing age (under 45) had been using oral contraceptives at the time of cerebrovascular accident (CVA). 16% and 20%, respectively, had used oral contraceptives at some time before the accident. 16 women were able to supply the name of the brand used at the time of CVA: 10 (63%) had used pills with estrogen content of 100 mcg and 6 (37%) pills with 50 mcg. On the other hand, in Finland during 1968-1971, only 30% of the pills used contained 100 mcg of estrogen. In the Health Security Area of South Finland (served by the Department), only 15.5% of the women under 45 years of age were oral contraceptors in 1971.