Objective The study was conducted to investigate the feasibility and effectiveness of thrombolytic therapy for femoral artery thrombosis after left cardiac catheterization in children. Methods Thrombolytic therapy with urokinase was carried out in children with femoral artery thrombosis after left cardiac catheterization. Patients were given a bolus injection of heparin (100u/Kg). 30000-100000u boluses of urokinase (UK) were injected intravenously, and then a continuous infusion of 10000-50000u/h was administered. Transcatheter thrombolysis was performed once previous procedures failed. Results Eight patients (age range 8 months to 7 years [3.1 ± 2.3 years], body weight 7kg to 20kg [13.1 ± 4.2kg]) presented lower limbs ischemia after left cardiac catheterizations was performed. Seven patients accepted thrombolytic therapy with UK. In 5 patients, peripheral intravenous thrombolysis was successful with restoration of a normal pulse. In the other 3 cases, peripheral intravenous thrombolysis failed, followed by successful transcatheter thrombolysis. The average duration of therapy was 7.25 ± 5.31h [1-17h]. The average dose of heparin and UK were 1600 ± 723u [800-3000u] and 268571 ± 177240u [50000-500000u], respectively. There were no statistically significant differences in partial thromboplastin time before and during UK therapy (40.6±22.3 to 49.9±39.2 seconds). However, the prothrombin time was significantly longer (12.7±2.58 to 48.1±18.6 seconds, P<0.05). Patency of the target vessel was evaluated in all the patients for 2 weeks and no occlusion recurred. Conclusion Thrombolytic therapy with UK is a safe and useful modality in children with femoral artery thrombosis after left cardiac catheterization.