Social workers in health care often argue that they must be professionally assertive in order to keep their values afloat in a stormy sea of change. The practice of health social work has traditionally been tied to a professional identity derived from a claim to expertise in the ‘psychosocial’ aspects of health and illness. This article briefly reviews relevant literature on health social work in institutional settings, with specific reference to the links between knowledge, credentials and a secure professional identity. Data from a small study is used to examine the problematic nature of professional identity and links between continuing professional education and status in health social work in New Zealand. Findings reveal practitioner concern that the knowledge claim of social work is weak and this impacts on their professional identity and status in multidisciplinary institutional settings.