A follow-up study of more than 65,000 healthy women aged 15 to 44 was conducted to assess the association between oral contraceptive use and thromboembolism, stroke, or nonfatal myocardial infarction from 1980 through 1982 at Group Health Cooperative of Puget Sound. A positive association existed between current oral contraceptive use and venous thromboembolism (rate ratio equals 2.8), but there was no positive association between current oral contraceptive use and stroke or myocardial infarction.