A preliminary study on infant mortality was done in the rural area of Nanggung, Bogor Regency, West Java in 1985. A sample of 11,718 villagers were observed for information on causes of death and expectation of life at birth by using historical prospective study. Infant mortality rate was 95.2 per 1,000 live births; death rate of 1—4 years age group was 13.7 per 1,000 midyear population; proporti-onate mortality ratio of the under-fives in relation to all deaths was 71.9 percent; crude death rate was 8.2 per 1,000 midyear population; expectation of life at birth was 66.8 years. The causes of death, grouped in different level of estimated years of life lost, were acute respiratory tracts, pulmonary infec-tions, diarrhoea, infections that can be prevented by immunization, low birth weight, birth injuries, accidents, chronic diseases and other unknown causes. Five of the 7 groups of causes of death were mainiy found in the under-fives group in the study area.