Insulin treatment is a basic pillar of complex care of patients with type 1 diabetes mellitus. Patients with type 1 diabetes mellitus are life-dependent from exogenous insulin administration. The most optimal method of insulin substitution in patients with type 1 diabetes mellitus is intensive insulin therapy (basal-bolus therapy). Intensive insulin therapy the most closely mimic the physiologic insulin secretion. In patients with type 2 diabetes mellitus insulin treatment is not inevitable for saving the life, but approximately in the period 5-10 years since the diagnosis of type 2 diabetes mellitus, majority of type 2 diabetics will require insulin treatment for achieving the goals for glycaemic control. At present there are used only human insulin in the Slovak Republic. Insulin analogues are synthetically prepared insulin with intentionally changed sequence of amino acids. Insulin analogues more closely match normal physiologic postprandial (lispro, aspart, glulisin) and basal (glargin, detemir) insulin secretion. Non- injectable forms of insulin (inhaled, oral, transdermal, tablet insulin) are perspectives of insulin treatment in the future. This year (only in the USA) using of inhaled insulin Exubera was approved. Introducing of Exubera to the market in the Slovak Republic is expecting in near future.