Accompanying the rise in the number of mental health agency personnel tasked with quality assurance and improvement (QA/I) responsibilities is an increased need to understand the nature of the work these professionals undertake. Four aspects of the work of quality assurance and improvement (QA/I) professionals in mental health were explored in this qualitative study: their perceived roles, their major activities, their QA/I targets, and their contributions. In-person interviews were conducted with QA/I professionals at 16 mental health agencies. Respondents perceived their roles at varying levels of complexity, focused on different targets, and used different methods to conduct their work. Few targets of QA/I work served as indicators of high quality care. Most QA/I professionals provided concrete descriptions of how they had improved agency services, while others could describe none. Accreditation framed much of agency QA/I work, perhaps to its detriment.