We present 2 patients who suffered from obstructive uropathy and received percutaneous nephrostomy diversion. After a series of studies, the diagnoses were transitional cell carcinoma and squamous cell carcinoma, respectively. Unfortunately, tumor seeding through a percutaneous nephrostomy tract developed after radical operation. Wide excision of recurrent tumors was performed and no local recurrence could be found after a follow-up more than 1 year later. Malignancy seeding through the percutaneous nephrostomy tract should always be kept in mind when we deal with patients of obstructive uropathy caused by suspected malignancy.