Sixty patients each of whom had a fracture of the lower limb a minimum of five years (median 11 years) previously were studied by photoplethysmography, foot volumetry, popliteal venous reflux and arterial Doppler measurements. The non-fractured limb was used as a control. Postphlebitic symptoms were present in 51% and signs in 49% of fractured limbs compared with 4% and 24% respectively in the control limbs. The incidence was greater in patients who had fractured 15 years or more previously than in those who had fractured 5 to 15 years previously. Eleven limbs had clinically disabling postphlebitic symptoms including venous ulceration. The postphlebitic syndrome following lower limb fractures in young patients is more common than generally appreciated and develops after a prolonged latent interval. A prospective randomised study using prophylactic anticoagulation for lower limb shaft fractures may be justified.