Diabetes mellitus is a disease in which a person has a high blood glucose level as a result of either because the body does not produce enough insulin (Type 1), or because the body cells do not properly respond or resistant to the insulin that is produced (Type 2). Insuin therapy is widely used in patients with these two types of diabetes. Modification of the human insulin molecule results in a slower distribution to peripheral target tissues, a longer duration of action with stable concentrations and thus a lower rate of hypoglycemia. Insulin analogs are synthesized to minimize unpredictable side effects of NPH (neutral protamine Hagedorn) insulin. Insulin detemir is an insulin analog that provides effective therapeutic options for patients with type 1 and type 2 diabetes. Several trials showed that insulin detemir did not display any significant differences in glycated hemoglobin (HbA1c) levels when compared to NPH and insulin glargine. It is comparable with insulin glargine in significantly reducing rates of all types of hypoglycemia. Clinical studies have demonstrated that detemir enabled significantly lower within-subject variability and no or less weight gain than NPH insulin and glargine. Recent pharmacodynamic studies have pointed out that detemir could be used once daily in many patients with diabetes. This review will focus on the toxicological profile of insulin detemir: pharmaco/toxico-kinetics and dynamics, safety/efficacy, adverse reactions, drug interactions, and its mutagenecity/carcinogenicity.