This paper addresses three related themes: (1) what is known about the relationship between diabetes mellitus and psychological distress; (2) therapeutic interventions for these psychological problems in people with diabetes; (3) recommendations for clinical practice and research. A review of the literature establishes the fact that our understanding of the association between diabetes and psychological problems is limited, and that what we know about the effectiveness of specific treatments for particular forms of psychological distress is even more limited. An explanation for this state of affairs is offered, along with recommendations for improving our ability to treat these problems more effectively.