Purpose: Radical cystectomy (RC) is a major surgical procedure accompanied with meaningful complications and countable perioperative mortality. To identify the risk factors predicting the perioperative morbidity and mortality is essential. The study aimed to identify relevant, patient-specific factors associated with 90-day mortality following RC, which may serve as a foundation for improving healthcare delivery to patients with bladder cancer. Methods: We investigated a sample of 1015 consecutive patients in order to identify predictors of 90-day mortality after RC. Beside tumor-related parameters, ASA classification, NYHA, Canadian Cardiovascular Society classification of angina pectoris, Charlson score, age, gender and the single conditions contributing to the Charlson score were included in the multivariable analyses. The patient data were collected retrospectively, except the ASA score that was obtained prospectively. Results: We identified a model containing the parameters age (OR 1.05, p = 0.023), ASA classification of 3–4 (OR 6.19, p < 0.001) and Charlson score (OR 1.22, p = 0.003) to predict 90-day mortality. Among the single conditions to the Charlson score, moderate or severe renal disease (OR 3.94, p < 0.001) and liver disease (OR 3.24, p = 0.037) were most closely related to 90-day mortality. Conclusions: Age, ASA classification and Charlson score as well as moderate or severe renal disease and liver disease appear to be independent predictors of 90-day mortality after RC. Given the highly significant association of ASA score with 90-day mortality and the relative ease and width disposability of this measure, this classification should be, after external validation, incorporated into daily clinical practice in treatment of patients planned to RC.