Hybrid closed-loop (HCL) insulin pump therapy is a promising development for the management of type 1 diabetes (T1D), but little is known about the transition period to HCL in a real-world setting. Here, we present novel data evaluating the HCL transition experience and its effect on diabetes distress. We evaluated 32 out of 150 anticipated participants who were about to transition (Arm A), or had recently transitioned (Arm B), from standard pump therapy to the MiniMed™ 670G HCL pump. Patients completed a baseline and 6-month post-transition diabetes distress survey using the T1-DDS. In the follow-up survey, patients’ trust in HCL and treatment satisfaction were also assessed. Finally, post-survey interviews were conducted for patients to elaborate on the successes and struggles of their HCL transition experience. No significant differences were observed between the 2 arms, so the sample was analyzed as a whole. After 6 months on HCL, significant reductions were observed in overall diabetes distress (p<0.0001), as well as powerlessness (p<0.005), management (p<0.001), hypoglycemia (p<0.005), and eating (p<0.0005) distress. Most patients (56%) indicated difficulty trusting HCL, however 80% reported that trust improved over time. Patient satisfaction was high (81%), however only 47% indicated that HCL met their expectations, 56% would recommend HCL to others, and 66% indicated frustration with the transition to HCL. Patients were divided on whether HCL increased (41%) or decreased (47%) the workload required to manage their T1D (12% neutral). Over half of patients (59%) felt that HCL was too complicated. Patients were divided on whether HCL was too much of a “hassle” to use (31% yes, 38% no, 31% neutral). Emerging themes from the qualitative data include numerous alarms, loss of sleep, and necessity of “phantom carbing.” Overall, HCL therapy significantly reduces diabetes distress, but the patient transition experience is varied in terms of trust, satisfaction, and comfort with the technology. Disclosure A. Dissanayake: None. E. Chow: None. A. White: Advisory Panel; Self; Abbott Diabetes, AstraZeneca, Boehringer Ingelheim (Canada) Ltd., Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk Canada Inc. J. E. Kapeluto: None. J. Mackenzie-feder: None. B. Schroeder: Advisory Panel; Self; AstraZeneca, Novartis Pharmaceuticals Canada Inc. M. Pawlowska: Advisory Panel; Self; Novo Nordisk.