Aim To review the literature estimating the cross-sectional prevalence of clinical depression in adults with Type 1 diabetes.Methods Electronic databases and published references were used to identify studies published between January 2000 and June 2004, with a previous meta-analysis used to identify studies before 1 January 2000.Results Between January 2000 and June 2004, a further five eligible studies were identified. Only one was a controlled study using diagnostic interviewing to determine rates of depression. Taking all of the eligible studies identified by the previous meta-analysis and this search, the prevalence of clinical depression in controlled studies was 12.0% for people with diabetes compared with 3.2% for control subjects. In studies with no control group, the prevalence of clinical depression was 13.4%.Conclusion There are wide-ranging differences reported in the various studies on the prevalence of depression in Type 1. diabetes. In view of the differing methods of diagnosis and small participant numbers, the results should be viewed with caution. A controlled study using diagnostic interviewing techniques to determine levels of depression is recommended to provide a clearer picture of both the prevalence and characteristics of that depression.