Assessment of the significance of the different insulins used in type 2 diabetes mellitus is of fundamental importance for routine treatment. Compared with human insulin, rapid acting insulin analogues have a faster uptake and a higher peak effect as well as a shorter duration of action. Long acting insulin analogues have a flatter action profile and a longer duration of action than NPH insulin. Consequently, insulin analogues generally allow an improved glycaemic control to be achieved. Moreover, differences relating to practical aspects are of importance (snacks and interval between injection and meals in the case of short acting insulin as well as mixing of suspensions and number of injections in the case of long acting insulins). The consequences for clinical practice are seen differently by countries as shown by a prescription rate of 50 % for insulin analogues in Germany compared with approximately 90 % in certain other European countries. One of the main reasons why questions remain is the lack of meaningful long-term studies on diabetes-related complications.