Feather picking is a common clinical presentation. The disorder can be frustrating to the client as well as the veterinarian both in terms of diagnosis and treatment. This article discusses a diagnostic approach to feather picking that begins by obtaining a detailed environmental, behavioral, and nutritional history. Suggestions are made for obtaining a minimum data base. Additional laboratory testing is often required to rule in or out a disease process. Diagnosing a behavioral or psychological feather picker can be achieved by ruling out organic disease.