OBJECTIVES:To investigate volume-outcome relationships in nephrectomy and cystectomy for cancer. MATERIALS AND METHODS:Data were extracted from the UK Hospital Episodes Statistics database, which records data on all National Health Service (NHS) hospital admissions in the England. Data were included for a 5-year period (April 2013-March 2018 inclusive) and data on emergency and paediatric admissions were excluded. Data were extracted on the NHS trust and surgeon undertaking the procedure, the surgical technique used (open, laparoscopic or robot-assisted) and length of hospital stay during the procedure. This dataset was supplemented by data on mortality from the UK Office for National Statistics. A number of volume thresholds and volume measures were investigated. Multilevel modelling was used to adjust for hierarchy and confounding factors. RESULTS:Data were available for 18 107 nephrectomy and 6762 cystectomy procedures for cancer. There was little evidence of trust or surgeon volume influencing readmission rates or mortality. There was some evidence of shorter length of hospital stay for high-volume surgeons, although the volume measure and threshold used were important. CONCLUSIONS:We found little evidence that further centralization of nephrectomy or cystectomy for cancer surgery will improve the patient outcomes investigated. It may be that length of stay can be optimized though training and support for lower-volume centres, rather than further centralization.