The efficacy of rt-PA treatment within 3 h in patients with acute ischemic stroke was recently demonstrated in two large, double-blind, randomized trials. The role of postthrombolytic heparin therapy in stroke still remains unclear as anticoagulation was not allowed during the first 24 h in most larger studies. The risk of combining thrombolytic with immediate anticoagulant therapy was evaluated in 43 consecutive patients with acute stroke. Thrombolysis (NINDS protocol) was followed by intravenous heparin aiming to double aPTT. Clinical course and CT were assessed after 24 h for signs of intracranial bleeding. The data of our series were compared to those of the present literature. Hemorrhagic conversion was found in 9 patients (21%), only one of them had symptomatic parenchymal hematoma (2.3%). In this small, open study the risk of symptomatic hemorrhagic complication after combined therapy does not seem to be markedly greater than after thrombolysis alone.