The present review concerns the current possibilities of insulin administration through the oral, rectal or nasal routes. The use of vehicle such as liposomes or various polymers protecting the hormone against the digestive enzymes allowed to improve the absorption of insulin after its oral administration. Moreover, the use of various surfactants favours the resorption of insulin through the intestinal, rectal and nasal mucosae. However until now, none of these routes has sufficient reliability and reproducibility to be considered for routine treatment of diabetes mellitus.