A pericaliceal haemangioma associated with papillary necrosis caused haematuria which led to nephrectomy. Seven similar vascular lesions were found on review of the surgical histopathology records from the last 25 years at the St Peter's Hospitals, Institute of Urology, London. In 4 of these there was histological evidence of damage to the renal papilla adjacent to the vascular abnormality; a possible mechanism for these changes is discussed. In all 8 cases the patients presented with haematuria and, in 5, abnormalities were seen on renal radiological investigation. Nephrectomy was performed in 5 instances and the remaining 3 patients were treated by partial nephrectomy. The presence of a vascular malformation was considered pre-operatively in 2 patients and in the remainder the diagnosis was first made on laboratory examination. In all patients haematuria ceased post-operatively and in 5 cases where follow-up information was available there has been no evidence of bilateral involvement.