Banjarnegara, a regency with a population of 678,000 located in a poor, mountainous region of Central Java, has become a focus of attention because of its Primary Health Care (PHC) programme. Since 1972, three-quarters of Banjarnegara's 279 villages have established a wide range of community-based health activities. Yet it is difficult to describe and analyse this programme, which has never had a specific design or master plan. Nor have there been large injections of funds from Indonesian government or international agencies. The programme runs on a modest budget, relying on an element that eludes many carefully planned, heavily funded development efforts--the voluntary participation of large numbers of local people. Some 4000 unpaid volunteers are largely responsible for planning, implementing and evaluating the programme. This article attempts to describe and assess the programme's achievements, limitations and possible wider relevance.