We present six cases of upper urinary tract diseases including tumors and inflammatory lesions in which the urine cytology rather than the radiological examinations was useful for their preoperative diagnoses. Three of the six cases had malignant diseases and the others had benign diseases. In all cases preoperative results of urine cytology were identical to histopathological findings of resected specimens; the cases with positive findings in urine cytology had ureter cancers and those with negative findings had benign diseases. Primary CIS of upper urinary tract was found in two of six cases, which is still uncommon in Japan. Since it is very difficult to make a preoperative diagnosis of primary CIS by radiological examinations, the present study showed that urine cytology is useful for its preoperative diagnosis. Recently endoscopic techniques for the diagnosis of upper urinary tract tumors are in clinical use. The ureteroscopic biopsy is recommended for the case in which the diagnosis using urine cytology is difficult.