OBJECTIVES: To describe demographic and clinical characteristics of diabetic patients who initiated basal insulin and assess their glycemic control.  METHODS: Physician encounters recorded in the General Electric EMR Database (2005-2010) were assessed. Patients with type II diabetes (T2DM) who initiated basal insulin between February 2006 and August 2009 were selected, with initiation defined as no prescription record of insulin in prior 15 months. Patients were followed for an average of 2.5 years after insulin initiation, and the proportion achieving A1C≤7% (“goal”) and time to achieving goal were assessed. Among patients who reached goal, the proportion of and time to A1C increasing above 7% (relapse) were analyzed. Cox proportional hazard models were estimated to identify demographic and clinical predictors of A1C goal achievement and relapse. RESULTS: Basal insulin initiators with T2DM (n=13,373) were on average 60 years old, 50.5% were females, 59.5% had A1C>8%, 59.7% were obese, and more than half used metformin (52.7%) or sulfonylureas (53.4%) before insulin initiation. A total of 5844 (44%) patients reached goal within one year since initiation, and 7699 (58%) reached goal during the ~2.5-year follow-up. The median time to reaching goal was 536 days (95% CI: 510-562). Older age, being white or male, lower baseline A1C values and no OAD use before insulin initiation were associated with significantly higher rates of reaching goal.  Among the patients who reached goal, 57.6% relapsed, and the median time from reaching the goal to relapse was 398 days (95% CL: 383-417).  Being Hispanic, higher baseline A1C values and OAD use at baseline were associated with significantly higher rates of relapse.   CONCLUSIONS: A high proportion of T2DM patients did not have adequate glycemic control after initiating basal insulin. Various factors existing prior to insulin initiation were related to successful treatment of T2DM. Further research into how to improve glycemic control is encouraged.