We evaluated the outcomes of 177 consecutive patients (43 women, 134 men) <40 years of age with premature atherosclerosis who underwent percutaneous coronary intervention. Women were younger, had more diabetes mellitus (37% vs 10%; p <0.001), but less hyperlipidemia (58% vs 75%; p <0.001) compared with men. In-hospital vascular complications and 1-year mortality rate or Q-wave myocardial infarction (7.9% vs 0.08%, p <0.01) were higher in women. By multivariable regression analysis, female gender was the only independent predictor of vascular complications (odds ratio, 14.1; 95% confidence intervals, 1.59 to 125, p = 0.01) and of 1-year mortality rate or nonfatal myocardial infarction (odds ratio, 12.5; 95% confidence interval, 1.14 to 111, p = 0.03). Women with premature coronary disease had a distinctive risk factor profile relative to men, with a predominance of diabetes and hypercholesterolemia, and were at higher risk of developing vascular and ischemic complications after percutaneous coronary intervention, warranting aggressive risk factor modification and vigilance in this population.