The application relates to an aqueous pharmaceutical formulation for use in the treatment of Type I or Type II Diabetes Mellitus, wherein the treatment reduces the risk of nocturnal hypoglycemia, said formulation comprising 200 - 1000 U/mL [equimolar to 200 - 1000 IU human insulin] of insulin glargine, with the proviso that the concentration of said formulation is not 684 U/mL of insulin glargine.