Data on 149 children who underwent retrograde arterial catheterization were studied to assess the frequency of femoral arterial thrombosis, and the safety and efficacy of systemic fibrinolytic therapy for this complication. Fourteen patients (9.4%) who had a pulseless extremity four hours after the catheterization were assumed to have femoral artery thrombosis. Thrombosis complicated patients were divided into two groups. The first group (7 patients) received only heparin treatment, and then 6 of them underwent thrombectomy. In the second group, 2 patients received only streptokinase, and 5 patients received streptokinase after heparin administration. Only 1 patient (who received streptokinase 1000 U/kg/hour after 1000 U/kg bolus) underwent thrombectomy in this group. The success rate was 86% (p<0.05). In another patient who had undergone sclerozan therapy for hemangioma and received streptokinase in the dose the previous patient received, symptoms of intracranial bleeding were noted at the sixth hour of therapy with reversal of the femoral pulses. These findings show that streptokinase is an alternative therapy to thrombectomy in the treatment of catheterization complicated arterial thrombosis. However, it is not as safe as previously mentioned, and must be avoided for the patients who may be at risk of arteriovenous malformation.