The present invention relates to methods for administration of insulin into the intradermal compartment of subject's skin, preferably to the dermal vasculature of the intradermal compartment. The methods of the present invention enhance the pharmacokinetic and pharmacodynamic parameters of insulin delivery and effectively result in a superior clinical efficacy in the treatment and/or prevention of diabetes mellitus. The methods of the instant invention provide an improved glycemic control of both non-fasting (i.e., post-prandial) and fasting blood glucose levels and thus have an enhanced therapeutic efficacy in treatment, prevention and/or management of diabetes relative to traditional methods of insulin delivery, including subcutaneous insulin delivery.