OBJECTIVE Bariatric surgery is associated with diabetes remission and prevention of diabetes-related complications. The ABCD, DiaRem, Ad-DiaRem, DiaBetter, and individualized metabolic surgery scores were developed to predict short- to medium-term diabetes remission after bariatric surgery. However, they have not been tested for predicting durable remission nor the risk of diabetes complications, nor compared with diabetes duration alone. RESEARCH DESIGN AND METHODS We identified 363 individuals from the surgically treated group in the prospective Swedish Obese Subjects study with preoperative type 2 diabetes and for whom data (preoperative age, BMI, C-peptide, HbA1c, oral diabetes medications, insulin use, and diabetes duration) were available for calculation of remission scores. Partial remission (after 2 and 10 years) was defined as blood glucose <6.1 mmol/L or HbA1c <6.5% (48 mmol/mol) and no diabetes medication. Information on diabetes complications (at baseline and over 15 years of follow-up) was obtained from national health registers. Discrimination was evaluated by area under receiver operating characteristic curves (AUROCs). RESULTS For 2-year diabetes remission, AUROCs were between 0.79 and 0.88 for remission scores and 0.84 for diabetes duration alone. After 10 years, the predictive ability of scores decreased markedly (AUROCs between 0.70 and 0.76), and no score had higher predictive capacity than diabetes duration alone (AUROC = 0.73). For development of microvascular and macrovascular diabetes complications over 15 years, AUROCs for remission scores were 0.70–0.80 and 0.62–0.71, respectively, and AUROCs for diabetes duration alone were 0.77 and 0.66, respectively. CONCLUSIONS Remission scores and diabetes duration are good predictors of short-term diabetes remission. However, for durable remission and risk of complications, remission scores and diabetes duration alone have limited predictive ability.