Background: Mortality following major urologic cancer surgery is a significant outcome to patients and providers. We utilized a population based cohort to test the hypothesis that the nature and number of perioperative complications impact the probability of mortality in major urologic surgery. Methods: Using the Premier Hospital Database we identified patients that underwent major urologic cancer surgery: radical prostatectomy (RP), radical nephrectomy (RN), or radical cystectomy (RC). Ninety-day complications were captured using ICD9 codes and complications were categorized according to the Agency for Healthcare Research and Quality Clinical Classification categories. The primary outcome was predicted probability of perioperative morality. Adjusted regression models were used and analyses were survey weighted. Models were adjusted for patient, hospital, and surgery characteristics, and we examined the predicted probability of mortality in three scenarios (no complication, index complication, or readmission complication). Results: From 2005-2013 we identified 630 828 RP, 306 532 RN, and 57 533 RC patients. At 90 days, 14.2% of RP patients had a complication, compared to 39% of RN patients and 68.3% of RC patients. Readmission rates at 90 days for RP were 1.9%, 5.9% for RN, and 19.9% for RC. For RN and RC the presence of a complication resulting in readmission compared to an index complication nearly doubled the predicted probability of mortality (RN 1.7% to 3.6%, and RC 3.9% to 6.8%). The number of complications during the index stay and on readmission compounded the impact on mortality. For RN and RC, 1 complication vs. 4 complications resulted in a nearly 3-fold increase in predicted probability of mortality. The nature of complications varied by incidence however, the three most common complications that resulted in the greatest increase in predicted probability of mortality across all three operations included pulmonary, cardiac, and renal complications. Conclusions: The number and nature of complications after major urologic cancer surgery impact the predicted probability of perioperative mortality and such data may be used to counsel patients when providing urologic cancer care.