Life expectancy in members of the general population has steadily improved in most countries since 1960. However, during the same period, the life expectancy of people with serious mental illness (SMI) has actually reduced. The majority of premature deaths result from natural causes, such as coronary heart disease. Obesity, a key risk factor for heart disease in this client group, might be caused both by unhealthy lifestyle behaviours and the side-effects of antipsychotic medication. Mental health nurses (MHN) nurses have an important role to play in improving the physical health of people with SMI. Evidence, however, suggests that they are often ambivalent about this role, and might perceive themselves as being inadequately trained and lacking in confidence. In this paper, we will argue that MHN need to re-evaluate their practice and recognize that the provision of physical health care is as important as other roles they occupy in relation to the care of people with SMI. We will also consider examples of best practice in physical health care, and discuss how these might be adopted by MHN and other professionals, in order to begin to improve services and to reduce health inequalities in this client group.