The “advanced hybrid closed-loop” (AHCL) systems represent the latest generation of Automated Insulin Delivery systems and have improved glycemic control in type 1 diabetes (T1D). To date, however, few studies with an observational period beyond 6 months have been reported, and even less beyond 12 months. In this observational real-world study we evaluated retrospectively Minimed™ 780G system’s efficacy to achieve and maintain glycemic control in T1D over a 24 month period. We enrolled 23 adult T1D patients with mean age 43,43±13,44 years, diabetes duration 27,56±12,85 years, HbA1c 7,6±0,57%, Total Daily Insulin dose (TDI) 38,82±15,28 units (T0). After AHCL system introduction, TIR%, TAR%, TBR%, CV%, HbA1c%, GMI%, mean glucose and TDI were evaluated at 14 days after the start of manual mode (M, during which AHCL was used as a Predictive Low Glucose Suspend system), at 14 days after the start of automated mode (A), at 3 (A3mo), 6 (A6mo), 12 (A12mo) and 24 (A24mo) months in A, comparing the A settings to M. We also investigated correlations between glycemic outcomes in A and variables evaluated at baseline as well as the average M period. We observed an improvement in glycemic control after 14 days of A respect to M. In particular: reduction of TAR% (p<0.0001), TBR% (p: 0.0269), CV% (p: 0.0008), mean glucose (p<0.0001), GMI% (p: 0.0148), increase of TIR% (p<0.0001). Results were confirmed at A3mo, A6mo, A12mo and A24mo. At A12mo and A24mo we observed a reduction of HbA1c% compared to T0 (p: 0.0004 and p<0.0001 respectively). After 14 days of A target values in relation to standardized CGM metrics have been achieved and maintained during 24 months. A24mo TIR% negatively correlated with T0 HbA1c% (p: 0.021), A24mo TAR% and A24mo HbA1c% positively correlated with T0 HbA1c% (p: 0.0042 and p: 0.0071 respectively) and A24mo GMI% with T0 HbA1c% (p: 0.0151). No correlation was found between A, A3mo, A6mo, A12mo and A24mo glycemic results and age, diabetes duration, TDI, average M period. Such results demonstrate the rapid and sustained improvement of glycemic control in adult T1D patients by an AHCL system, able to achieve glycemic targets and maintaining them over 24 months.