Objectives: There is an urgent need for more effective and efficient depression treatments in diabetes. We developed a diabetes-specific version of the Dutch web-based ‘Coping with Depression’ (CWD) course. Here, we report on the development, reach, patients’ reasons for choosing our intervention and their characteristics. Methods: The CWD programme was amended for use in diabetes patients with co-morbid depression. Data were collected using a telephone interview, self-report questionnaires, and medical records. Results: Adding diabetes-specific topics to an effective web-based depression programme resulted in an 8-lesson intervention (“www.diabetergestemd.nl”), with minimal guidance by coaches. In the framework of a randomised trial, the intervention attracted serious interest of 540 patients. After screening, 255 depressed diabetes patients were enrolled. Less than half had a history of depression treatment; 80% reported the diabetes-specific approach to be an important reason for signing up. Conclusion: We successfully developed a diabetes-specific version of the web-based CWD course, which attracted a large group of patients. Our results affirm the importance of addressing diabetes-specific issues in the context of depression treatment. Practice implications: Our intervention could be implemented on a large scale at low costs, and may serve as a model on how to develop other illness-specific online self-help interventions.