The Beck Depression Inventory (BDI) is one of the most commonly used depression measurement instruments. Mental health nurses often utilize the BDI to assess the level of depression in clients, and to monitor the effectiveness of treatments such as antidepressants and electroconvulsive therapy. Despite the widespread use of the BDI in both clinical practice and research, there is surprisingly little nursing literature critically examining the BDI or its use by mental health nurses. This paper reviews the origins, purpose, and format of the BDI, discusses some of the strengths and limitations of the BDI, and concludes with some implications for mental health nursing.