This article explores mental health nurses' diabetes training needs. A survey of inpatient and community mental health nurses was undertaken using a 16-item self-reporting questionnaire. Two hundred and twenty questionnaires were sent out and 138 returned, providing a response rate of 63%. Analysis shows that mental health nurses are currently involved in a range of diabetes care activities, however, their knowledge and skills may not be up to date. Mental health nurses also report the growing impact of diabetes care on their workload. Areas of identified training needs include taking blood glucose readings, giving dietary advice, liaison with diabetes nurse specialists and weight management. Mental health services and education providers need to consider developing specific training courses for mental health nurses.