Diabetes is in the fifth place among the top ten leading causes of death in Taiwan, and it is frequently accompanied by other chronic diseases. Diabetes not only menaces patients' life, but also is a heavy burden to family and society. During the disease process, most of the patients with diabetes will experience a series of psychological impacts. For example, patients with diabetes frequently experience depression, and its prevalence rate is two times (or more) higher than that of general patients. In order to investigate how depression affects disease control of diabetes, this study conducted literature review to summarize the incidence of diabetes and depression, pathogenesis, and adverse effects of depression on patients with diabetes. It also summarized several depression scales commonly used in patients with diabetes. We hope that this review could serve as references for clinical caregivers to facilitate the specific evaluation and referral, introduction intervention of depression on patients with diabetes. Furthermore, we also proposed specific suggestions on the aspects of patients, medical and nursing personnel, and research.