The aim of this case study was to describe and analyse the basic pre-conditions for an intervention programme focusing upon mental health promotion and prevention of depression in an elderly community group and to discuss the psychiatric nurse's community-oriented health promotion work. The intervention programme, which was led by a psychiatric nurse, was built on intersectorial co-operation between public and voluntary organizations, development of social networks to promote social support, and target group participation. The nurse's function in the community-oriented work was to act at the individual, group and society level, as well as to mobilize resources among individuals and organizations, in order to create a favourable interaction, resulting in health and empowerment for the individual. Pre-conditions for leading this work were: knowledge of health and mental all health among the elderly, investigation methodology, knowledge about the local society, as well as pedagogical, supervisory and social competence.