In the treatment of patients with diabetes, the tear of hypoglycemia is a major barrier to initiating, maintaining, and/or intensifying insulin therapy. Insulin detemir (Levemir [Novo Nordisk A/S, Bagsvaerd, Denmark]) is a novel, long-acting, basal insulin analog associated with a reduced risk of hypoglycemia that is available to improve glycemic control. This article discusses clinical trial data on the safety and efficacy of insulin detemir in patients with type 1 and type 2 diabetes. In additions, results from the German cohort of the Predictable Results and Experience in Diabetes through Intensification and Control to Target: An International Variability Evaluation (PREDICTIVE study, a large, multinational observational study examining the clinical effectiveness and safety of insulin detemir, are reviewed. Finally, an evaluation of these data serves to show how the highly predictable action of insulin detemir translates into effective glycemic control with a lower incidence of hypoglycemia.