BACKGROUND: Radical cystectomy (RC) is the standard treatment for muscle invasive bladder cancer, but approximately half of all patients will ultimately succumb to disease progression despite apparent cure with extirpative surgery. Elderly patients are at especially high risk of advanced disease and may benefit from perioperative systemic therapy. OBJECTIVE: To assess the real-world benefit of adjuvant chemotherapy (AC) in patients ≥75 years old. METHODS: We retrospectively reviewed patients who underwent RC for non-metastatic urothelial carcinoma of the bladder (UCB) from 12 participating international medical institutions. Kaplan-Meier survival curves and Cox regression models were used to assess the association between age groups, administration of AC and oncological outcome parameters such as recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS). RESULTS: 4,335 patients were included in the analyses, of which 820 (18.9%) were ≥75 years old. These elderly patients had a higher rate of adverse pathologic features. In an univariable subgroup analysis in patients ≥75 years with lymph node metastasis, 5-year OS was significantly higher in patients who had received AC (41% vs. 30.9%, p = 0.02). In a multivariable Cox model that was adjusted for several established outcome predictors, there was a significant favorable association between the administration of AC in elderly patients and OS, but no RFS or CSS. CONCLUSIONS: In this large observational study, the administration of AC was associated with improved OS, but not RFS or CSS, in elderly patients treated with RC for UCB. This is of clinical importance, as elderly patients are more likely to have adverse pathologic features and experience worse survival outcomes. Treatment of UCB should include both a multidisciplinary approach and a geriatric evaluation to identify patients who are most likely to tolerate and benefit from AC.