Chronic depression is a common disorder which causes significant impairment and enormous treatment costs. Traditional pharmacological and psychological treatment approaches have shown only modest success. The Cognitive Behavioral Analysis System of Psychotherapy (CBASP) by James McCullough is the only therapy developed specifically for chronic depression. It integrates behavioral, cognitive, and interpersonal strategies. The approach is supported empirically and shown to be effective. This article presents the state of the art regarding research in psychotherapeutic treatment for chronic depression. In addition, the development of the approach and therapeutic strategies and techniques of CBASP are described.