The aim of this study was to evaluate the prevalence of arterial hypertension and other risk factors in patients suffering from peripheral arterial disease (PAD) in two clinical samples (1.: 102 patients with PAD 69 M, 33 F, studied in our angiology laboratory, matched for sex and age with 102 healthy volunteers; 2.: 184 hospitalized patients, 80 M, 104 F, mean age 57.2 +/- 10.8, with PAD) and in two epidemiological cohorts (1.: Trabia Study, 835 subjects; 2.: Casteldaccia Study, 723 subjects). All patients were subjected to a full clinical and laboratory examination, including the determination of the ankle/arm pressure ratio (Winsor index, positive for PAD when lower than 0.95). In the first clinical study we observed a significantly (p < 0.01) greater prevalence of arterial hypertension (51.9 vs 9.8%), hypercholesterolemia (48.2 vs 21.6%), hypertriglyceridemia (53.7 vs 26.1%), smoking habit (64.3 vs 44.2%), and hyperglycemia (26 vs 7,9%) in PAD patients than in controls. In the second clinical study considering separately the patients under and over 65 years, all risk factors resulted to be more prevalent in younger people than in the aged, except for diabetes and hypertension. In our epidemiological experience, the prevalence of PAD increases with aging, above all in males. In the Trabia Study the risk factors, more associated with PAD, were hypercholesterolemia, smoking and obesity (41.18%) in males and hypertension and hypercholesterolemia (33.3%) and obesity (25%) in females. In the Casteldaccia Study the most important risk factors were smoking (64.28%), hypercholesterolemia (42.86%) and hypertriglyceridemia (35.71%) in males, and obesity (60%), hypercholesterolemia (30%) and diabetes (20%) in females. Cholesterol levels and smoking were significantly higher in PAD patients than in the general population, whereas hypertriglyceridemia and glycemia were not. Arterial hypertension was significantly associated with PAD in the Trabia but not in the Casteldaccia Study. Obesity was significantly associated to PAD in females in both studies. In the Casteldaccia Study, lower HDL-cholesterol levels were observed in PAD patients, above all in males, whereas significantly greater Apo-B values and lower Apo-A1 levels (in males) were shown. The different levels of associated risk factors and their prevalence in PAD patients confirm the multifactorial pathogenesis of atherosclerosis. The exact role of each risk factor in the genesis of PAD is difficult to be evaluated due to the complex biological and statistical interrelationships among different risk factors. However, the management of associated risk factors may favourably influence the risk profile in each patient suffering from PAD.