Glanzman thrombasthenia is a rare hematologic disorder characterized by qualitative thrombocyte abnormality. Patients present with episodic mucocutaneous bleeding. Thrombosis is a paradox phenomenon observed in patients with Glanzman thrombasthenia and generally considered as a treatment complication. We present a 16-year-old girl referred for severe flank pain beginning after treatment of hematuria due to Glanzman thrombasthenia. The patient underwent endoscopy for further diagnosis and treatment because of the failure of radiologic evaluation. Although the resolution of the large clots was obtained with streptokinase instillation via the ureteral catheter, clot was mobilized with gentle insertion of ureteral catheter in the present case. Blood Coagul Fibrinolysis 22:735-737 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.