BACKGROUND Aneurysms of the popliteal artery are rare events with an estimated incidence of 0.1-2.8%. Their clinical importance depends on their propensity to cause thromboembolic complications or to rupture (18 to 31% of cases). This study was designed to assess the advantages of elective treatment of asymptomatic popliteal artery aneurysms so as to avoid the severe clinical manifestations that eventually arise if they remain untreated. METHODS From 1980 to 1995, in our department we treated 28 popliteal aneurysms in 23 patients (19 elective operations and 6 emergencies). Three of the aneurysms proved amenable to fibrinolytic therapy alone. Follow-up lasted a mean 48 months (range 3 months to 15 years) in 20 patients (23 revascularizations). RESULTS Global patency was 91.3%. Two thrombosed bypasses were treated by thrombolysis; in one case it did not resolve the ischaemia and the leg was amputated. In one case only, a graft became infected but this responded to conservative therapy with drainage and antibiotics. CONCLUSIONS These findings suggest that popliteal aneurysms with good distal run-off should be repaired electively. Completely thrombosed aneurysms with coexistent limb-threatening ischaemia should be treated initially by thrombolysis. This will usually restore run-off and in some cases offers a valid alternative to emergency surgery for limb salvage.