In the treatment of peripheral obliterating arteriopathy (POA) physical training provides clear results in terms of increased walking autonomy; it is still not fully clear whether the positive effects of physical training can be further improved by concomitant back-up drug therapy. For this purpose 374 patients of both sexes, with a mean age of 64 years, suffering from chronic peripheral obliterating arteriopathy of the lower limbs were enrolled in a controlled open clinical trial, instructed to follow a programme of physical training and randomly allocated to low dose treatment with heparin calcium (12,500 IU/day) for 6 months. An improvement in the claudicometric parameters (free gait interval, absolute gait interval and recovery time) measured at constant speed and in the resting Winsor ankle/arm index of the most severely damaged limb were observed in both groups. These improvements were significantly greater in the group receiving pharmacological treatment (p < 0.01) and efficacy increased in line with basal deambulatory impairment. The results obtained and the good tolerance of the drug underline the clinical efficacy of heparin calcium at low doses in association with a physical training programme in patients suffering from Fontaine's stage II peripheral obliterating arteriopathy.