The clinical course and association with other urothelial carcinomas was studied in 80 patients with carcinoma of the renal pelvis. At the time of diagnosis macroscopic haematuria was the most common symptom. Urography and retrograde pyelography gave the most accurate diagnoses. Sixty-eight patients (85%) had transitional cell carcinomas, 39 had a history of another urothelial carcinoma either before or after the diagnosis of the renal tumour, usually in the urinary bladder. A previous urothelial carcinoma together with a small renal tumour were predictive of the subsequent development of another urothelial tumour. Regular cystoscopy is recommended during follow-up because of the short observed interval between the development of carcinoma of the renal pelvis and a subsequent urothelial malignancy. The overall five-year survival was 20%. Survival did not depend on the operation, but was significantly related to the extent of locoregional or distant metastases at the time of diagnosis. Patients with such renal tumours that were preceded by or associated with other urothelial carcinomas had a more favourable median survival (42 months) than patients whose renal tumour was their first urothelial carcinoma (19 months).