Health care staff knowledge of mental health is vital in the provision of quality care for older people in residential aged care settings. This paper aims to describe mental health knowledge competence of health care staff in residential aged care through a review of existing literature and to explore the link between knowledge, attitudes and education about older people and mental health. A literature review was conducted using electronic databases and library catalogues to identify articles published in English during the period 1982-2002. There is insufficient evidence within the literature to draw conclusions about staff knowledge levels in relation to mental health, however, the literature identified a link between continuing education, knowledge levels and staff attitudes to older people with mental health disorders. Future studies are needed to investigate existing levels of mental health knowledge among health care staff in residential aged care and to identify and evaluate strategies to enhance their ability to provide care for this population.