Over a 12 month period all patients but one presenting to our hospital with occluded prosthetic grafts were treated by thrombolysis using local pulsed administration of tissue-type plasminogen activator (t-PA). There were 30 interventions in 23 patients but in one patient no thrombolytic was given after aspiration of pus from the graft. Thrombolysis was attempted in the remaining 29 procedures. 22/29 (76%) of these procedures were performed by direct puncture and catheterization of the occluded graft and in a further six (21%) access was from a non-occluded femoral artery or graft. In one case the graft was accessed surgically. Supplementary angioplasties were performed in 15 cases (52%). Complications requiring surgery occurred in four (14%) with a further seven minor complications. There were no deaths. A lower rate of complications occurred in the grafts entered by direct puncture. Thrombolysis was achieved in all but one case taking an average of only 2.5 h but was only maintained beyond the end of the procedure in 21/29 (72%). An underlying cause for occlusion was identified and treated where possible, e.g. haematological or clotting abnormalities or inflow or outflow stenoses. There was a high rate of reocclusion but with repeat procedures when necessary patency was maintained in 10/22 patients (45%) on follow-up at 1 to 12 months. The best results were obtained with lysis of occluded femoro-femoral crossover grafts.