The purpose of this study was to evaluate the efficacy of intraarterial low-dose recombinant tissue plasminogen activator (rt-PA) in patients with acute or subacute thrombosis of the native arterial system or in an arterial artificial or venous by-pass graft. Twenty patients with 22 cases of thrombosis received intraarterial thrombolysis during the period 1.1.1995 to 31.12.1995. Ten patients (50%) achieved complete radiological thrombolysis, and in seven patients (35%) partial thrombolysis was achieved. Half of these patients required a subsequent PTA or an operation. There were only three patients (15%) where no lysis occurred. The results seemed very satisfactory and we conclude that thrombolysis should be considered as the first-choice treatment in this category of patients. The indications may be extended to patients with critical ischaemia with the introduction of the pulse-spray technique as the time to complete lysis is considerably shorter with this technique.