The efficacy of thrombolysis was retrospectively studied in patients with acute on chronic ischaemia in the lower extremity. A total number of 68 thrombolytic treatments were given to 65 patients, 58 (85%) because of native arterial occlusions and 10 (15%) because of occluded grafts. Tissue plasminogen activator was the lytic agent used in all patients. In native arteries, thrombolysis alone was successful in 15 (52%) out of 29 legs, whereas 22 (85%) out of 26 thrombolyses followed by angioplasty or surgery were effective. Thrombolysis alone was successful in two and failed in five out of 10 occluded grafts. Patency was achieved by combination with surgery in the other three cases. Twelve-month patency was 34% after thrombolysis alone and 69% (P < 0.05) when combined with surgery or angioplasty. The 30-day mortality rate was 9%. Thrombolysis can be used alone in acute on chronic ischaemia in the lower extremities. The immediate and the long-term results are clearly improved when thrombolysis is combined with angioplasty or reconstructive surgery to treat the underlying cause.