The group practice project in Naestved aims at introducing certain principles of community medicine in the primary health sector with the object of contributing towards an integrated, health-promoting effort at local community level. Naestved has five group practices with a total of 11 general practitioners. Over one third of the 43,000 inhabitants of the community are registered as patients with this medical centre. The focus is on prevention of ischaemic cardiovascular disease, and the project has four phases: Planning and introduction of the project in the local community. Epidemiologic study of the knowledge and attitudes to cardiac disease, known risk factors and prophylaxis in the population. Epidemiologic research and clinical practice including integration of research and intervention, community diagnoses as regards blood pressure and analyses of risk factors among persons in the intervention programme. Evaluation of the intervention programme. The phases of the project hitherto undertaken are described and the population corresponding to phase three is characterized. A total of 10,202 persons were investigated.