Background Peripheral arterial disease (PAD) is associated with an increased risk for mortality. We sought to assess the prevalence of PAD and its risk factors in a population-based sample. Methods We examined 1554 males and 1759 females with a mean age of 59 years who attended a Framingham Offspring Study examination from 1995 to 1998. PAD was defined by an ankle-brachial blood pressure index of <0.9. Age- and sex-adjusted and multivariable logistic regression analyses were performed to identify factors associated with PAD. Results The prevalences of PAD, current intermittent claudication, lower extremity bruits and surgical intervention were 3.9%, 1.9%, 2.4% and 1.4% in males and 3.3%, 0.8%, 2.3% and 0.5% in females. Hypercholesterolemia, high-density lipoprotein cholesterol, triglyceride, diabetes, hypertension, current smoking, pack-years of smoking, body mass index, fibrinogen, and prevalent coronary disease were associated with PAD in age- and sex-adjusted analyses. Odds ratios and 95% CIs for significant associations identified from multivariable analyses are as follows: each 10 years of age, 2.6 (2.0, 3.4); hypertension, 2.2 (1.4, 3.5); smoking, 2.0 (1.1, 3.4); 10 pack-years of smoking, 1.3 (1.2, 1.4); 50 mg/dL of fibrinogen, 1.2 (1.1, 1.4); 5 mg/dL of high-density lipoprotein, 0.9 (0.8, 1.0); coronary disease, 2.6 (1.6, 4.1). Conclusions Smoking cessation and hypertension control are important goals in the aim to reduce PAD and its associated impact on quality of life, functional decline, and risk for subsequent cardiovascular disease. (Am Heart J 2002;143:961-5.)