A series of 108 renal tumour nephrectomies carried out between 1975 and 1984 was studied to determine the prognostic statistical significance of the relationship between venous involvement and various pathological features. Tumour size, spread, histological grade and lymph node involvement were compared between V0 tumours (58%), V1 (32%) and V2 tumours (10%). Actuarial 5-year survival rates revealed a poor prognosis with venous involvement (V0 66%, V1 27%, V2 33%). Tumours larger than 10 cm with perirenal spread and of higher histological grade were significantly related to venous involvement. Survival between renal vein involvement and inferior vena caval extension was statistically similar, but it was influenced by tumour size and higher grade. Perirenal spread and nodal involvement were poor indicators.