The function of cutaneous primary afferent unmyelinated nerves (C-fibres) was assessed by measuring axon reflex vasodilatation in the skin over the arms and feet of 15 elderly patients with chronic venous ulcers using a laser Doppler flowmeter. Dilatation of skin microvasculature in response to nerve-independent stimuli was also assessed. Results were compared with those of control subjects matched for age and sex. The chronic venous ulcer group showed reduced axon reflex vasodilatation in the feet but not the arms. Response to nerve-independent vasodilators was similar in both ulcer patients and controls in arms and feet. Local impairment of C-fibre function may partly explain the increased incidence and resistance to healing of leg ulcers in old people.