OBJECTIVE The SOLVE study investigated the initiation of basal insulin in patients with type 2 diabetes on oral antidiabetic (OAD) treatment and outcomes in patients with varying levels of glycemic control at baseline. METHODS This was an observational cohort study conducted in 10 countries using insulin detemir. Data were collected at 3 clinic visits (baseline, 12-week interim, and 24-week final visit). RESULTS A total of 13,526 (77.9%) patients were included in the glycosylated hemoglobin A1c (HbA1c) subset analysis. Patients were grouped according to pre-insulin HbA1c values as follows: HbA1c <7.6% (n = 2,797); HbA1c 7.6-9% (n = 5,366), and HbA1c >9% (n = 5,363). A total of 27 patients experienced serious adverse drug reactions (SADRs) and/or severe hypoglycemia (3, 10, and 11 patients with pre-insulin HbA1c <7.6%, 7.6-9.0%, and >9.0%, respectively). All patient subgroups realized improvements in HbA1c, with the pre-insulin HbA1c >9% subgroup having the largest HbA1c reduction (-2.4% versus -0.9% and -0.2% for HbA1c subgroups 7.6-9% and <7.6%, respectively). In the total cohort (n = 17,374), the incidence of severe hypoglycemia decreased from 4 events per 100 person years to <1 event per 100 person years by final visit; the incidence of minor hypoglycemia increased from 1.6 to 1.8 events per person year. CONCLUSIONS In this study, insulin initiation was delayed until late in disease course, and overall concordance with internationally recognized guidelines was low. The initiation of once-daily insulin detemir was associated with substantial improvements in glycemic control and was not associated with an increase in severe hypoglycemia or weight gain.