During a cross-over-study in 12 ambulant patients the effects of Optisulin -Depot CR in comparison to Depot-Insulin Hoechst klar CR were examined. After a period with Depot-Insulin Hoechst klar CR patients got Optisulin -Depot CR in the same dose and with the same diet. A week later patients took Depot-Insulin Hoechst klar CR once again. The different blood-sugar-curves corresponded to each other, but Optisulin -Depot CR showed more initial effect. The use of Depot-Insulin Hoechst klar CR is an advantage, because, Optisulin -Depot CR is neutral and no depot-substances are contained. Therefore, less allergic reactions are expected.