Abstract Many muscle-invasive bladder cancer (MIBC) patients are not getting curative treatment, there remains an undertreated/underserved population and a huge unmet need. Some are not good surgical candidates and others decline a radical cystectomy given concerns regarding its morbidity. Trimodality therapy (TMT), comprising of a maximal transurethral resection of bladder tumor (TURBT) followed by chemoradiation (with salvage cystectomy reserved for those that incur a muscle-invasive recurrence), has emerged as a viable bladder-preserving alternative to radical cystectomy for selected patients. In clinically-matched cohorts, survival is comparable to radical cystectomy in the modern era. More than 85% of contemporary patients keep their own native bladder and long-term quality of life after bladder preservation is good. Salvage cystectomy is feasible and can be curative for those with MIBC recurrences. TMT is now supported by numerous clinical guidelines, including NCCN (category 1 recommendation for stage II and IIIA). There are opportunities to continue to optimize clinical staging of disease (e.g. MRI), delivery of RT (e.g. image guidance, adaptive delivery, dose escalation, hypofractionation, field design) and systemic therapies (e.g. concurrent, neoadjuvant and adjuvant, including possibly immunotherapy) to improve outcomes. Ongoing trials (such as SWOG/NRG 1806 which recently closed to accrual) will inform the addition of immunotherapy to TMT. Validation of biomarkers in independent cohorts and in prospective trials is necessary to further guide bladder preservation therapy for MIBC and for personalized treatment selection. Ultimately, MIBC patients should be seen in a multidisciplinary environment where informed decision making by the patient is key. Citation Format: Jason A. Efstathiou. Current state of the art: Bladder-preserving trimodality therapy for muscle-invasive bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr IA013.