Background: Muscle invasive bladder cancer (MIBC) comprises 25% of all bladder cancers at the time of diagnosis. Radical Cystectomy (RC) has traditionally been the gold standard curative treatment for MIBC. Trimodality therapy (TMT) with maximal transurethral resection of bladder tumor, chemotherapy, and radiation is a treatment alternative and Category 1 recommendation by the NCCN. TMT has shown equivalent survival for carefully selected patients. However, the comparative cost effectiveness between RC and TMT is unknown. Therefore, the purpose of this study was to compare the cost-effectiveness of RC versus TMT for MIBC. Methods: We developed a Markov model using TreeAge software to simulate a 5-year outcome for one million 65-year old hypothetical patients with MIBC undergoing either RC or TMT. Hypothetical patients in the RC treatment pathway would have an adverse event, no adverse event, or immediate death after surgery. After RC, patients either would have no evidence of disease or transition to locoregional recurrence, metastatic recurrence, or death. Hypothetical patients in the TMT treatment pathway would either have an adverse event or no adverse from treatment. After TMT, patients either would have disease-free bladder intact survival or transition to locoregional failure, metastatic recurrence, or death. Patients with locoregional failure from TMT transition into non-salvageable disease or salvageable disease. Patients with salvageable disease prompted a salvage cystectomy. Model probabilities and utilities were extracted from the literature. Costs were derived from 2019 National Medicare Fee Schedule. Results: RC and TMT were associated with quality adjusted life years (QALY) of 2.88 and 3.38 respectively (incremental QALYs of 0.5 favoring TMT). The mean costs of RC and TMT were $37,107 and $23,916 respectively. TMT was less expensive with an incremental cost of $13,191. Conclusions: In patients aged 65 and older with MIBC, TMT was the dominant strategy as compared to RC, as it was both cheaper and associated with increased QALYs based upon model assumptions. The results of this study are the first to evaluate the cost effectiveness of RC and TMT.