Background and Aims: Propofol, a widely used sedative in GI endoscopic procedures, is associated with cardiorespiratory suppression. Remimazolam is a novel ultrashort-acting benzodiazepine sedative with rapid onset and minimal cardiorespiratory depression. This study compared the safety and efficacy of remimazolam and propofol during EUS procedures. Methods: A multicenter randomized controlled study was conducted between October 2022 and March 2023 in patients who underwent EUS procedures. Patients were randomly assigned to receive either remimazolam or propofol as a sedative agent. The primary endpoint was cardiorespiratory adverse events (AEs) during the procedure, including desaturation, respiratory depression, hypotension, and tachycardia. Secondary endpoints were the time to achieve sedation, recovery time, quality of sedation, pain at the injection site, and satisfaction of both endoscopists and patients. Results: Four hundred patients enrolled in the study: 200 received remimazolam (10.8 ± 7.7 mg) and 200 received propofol (88.0 ± 49.1 mg). For cardiorespiratory AEs, the remimazolam group experienced fewer occurrences than the propofol group (8.5% vs 16%, P = .022). A nonsignificant trend was found toward less oxygen desaturation (1.0% vs 3.5%, P = .09), respiratory depression (.5% vs 1.5%, P = .62), hypotension (2.5% vs 5.5%, P = .12), and tachycardia (4.5% vs 5.5%, P = .68) with remimazolam than with propofol. Remimazolam showed a shorter induction time than propofol while maintaining comparable awakening and recovery times. Injection site pain was significantly lower in the remimazolam group than in the propofol group. The remimazolam group demonstrated a significantly higher quality of sedation and satisfaction scores than the propofol group, as evaluated by both endoscopists and patients. Conclusions: Remimazolam was superior to propofol in terms of safety and efficacy during EUS examinations. (Clinical trial registration number: KCT 0007643.)