Diabetes is one of the leading threats to the health of Australians-it is a large health, social and economic burden for individuals with the disease, their families and the community. 'National Diabetes Register: statistical profile 1999-2005' is the third statistical report of the National Diabetes Register (NDR). The NDR records new cases of insulin-treated diabetes. This report describes the characteristics of registrants, including type of diabetes, age at diagnosis, sex, geographical location, country of birth, Indigenous status, mortality and also provides incidence estimates. This report plays an important role in monitoring the levels and trends of diabetes in Australia and as a resource for researchers, policy makers, health professionals and anyone interested in diabetes in Australia.