We report the successful surgical treatment of two cases of renal vein thrombosis, each occurring early after kidney transplantation. Prompt intervention was a result of accurate diagnosis by color Doppler ultrasonography. Invasive radiological procedures were not useful. Although recent advances in thrombolytic therapy have created several alternatives to open surgery, the rationale for surgical exploration in these cases was to remove the thrombus quickly, to avoid the postoperative bleeding complications of thrombolytic therapy, and to correct any technical or anatomic problems.