One hundred and twelve South Indian males with non-diabetic peripheral vascular disease of the lower limb were classified clinically into three groups according to the level of obstruction (aorto-iliac, 26 patients; femoropopliteal, 46 patients; distal, 40 patients). Arteriography was done in 65 patients and serum lipid estimations in 69. In the aorto-iliac group the mean age was 45 years (+/- 11.6 s.d.); 23 per cent had hypertension, 28 per cent polycythaemia and 55 per cent hyperlipidaemia. Aortography suggested atheroma in most. In the femoropopliteal group the mean age was 39 years (+/- 12.8); 22 per cent had hypertension, 11 per cent polycythaemia and 21 per cent hyperlipidaemia. Arteriography showed lesions typical of atheroma in many and was consistent with thrombo-angiitis obliterans in some. In the distal group the mean age was 37 years (+/- 9.8); 8 per cent had hypertension, 20 per cent polycythaemia, 25 per cent hyperlipidaemia and 20 per cent had distal arterial disease of the upper limb. Arteriography was consistent with thrombo-angiitis obliterans in most cases. Atheroma seemed to be implicated in 96 per cent of the aorto-iliac group and in 64 per cent of the femoropopliteal group.