BACKGROUND:We aimed to determine the effects of laparoscopic adjustable gastric band (LAGB) on beta-cell function in overweight people with type 2 diabetes and to assess the relationship between baseline beta-cell function and glycemic outcomes. METHODS:We studied 44 overweight but not obese people with type 2 diabetes who participated in a randomized trial whose primary outcome was the rate of diabetes remission after 2 years of multidisciplinary diabetes care (MDC group) or multidisciplinary care combined with LAGB. Dynamic beta-cell function was assessed by intravenous glucose challenge, and basal beta-cell function (HOMA-B) and insulin sensitivity (HOMA-S) were determined using the homeostatic model. RESULTS:Twelve LAGB participants and two MDC participants were in diabetes remission at 2 years. HOMA-S and the C-peptide response to intravenous glucose increased significantly in LAGB but not in MDC participants. The insulin response to glucose did not change in LAGB participants, whereas their fasting C-peptide/insulin ratio increased. Baseline measures of beta-cell function correlated with diabetes remission but not with reduction in HbA1c following LAGB. CONCLUSIONS:In overweight people with diabetes, LAGB improves endogenous beta-cell function after 2 years. Baseline beta-cell function correlated with diabetes remission, but not with HbA1c change following LAGB.