Smoking increases the risk of lung cancer and cardiovascular disease among persons of both sexes. The risk of cardiovascular disease is further increased among users of oral contraceptives who smoke, particularly those who are ≥35 years old or carry the coagulation factor V Leiden mutation. Other important cardiovascular disease risk factors in women include waist/hip girth ratio >0.8, high concentration of low-density lipoprotein cholesterol (>115 mg/dL), high triglyceride level (≥150 mg/dL) with low concentration of high-density lipoprotein cholesterol (≤45 mg/dL), high ratio of total cholesterol/high-density lipoprotein (4.0), high ratio of low-density lipoprotein/high-density lipoprotein (3.0), glucose values ≥100 mg/dL, hypertension, lack of physical activity, and high-fat diet. Most excess cardiovascular disease among users of oral contraceptives is due to thrombosis (not atherosclerosis); studies indicate that the lower the oral contraceptive estrogen dose is, the lower is this risk. Oral contraceptives containing the third-generation progestins desogestrel and gestodene have been associated with greater risks of venous thromboembolism than are associated with older progestins, although there is some controversy surrounding these findings. (Am J Obstet Gynecol 1999;180:S349-56.)