PIP: The sub-center is the lowest service unit in the government sponsored health program in India, and the unit most accessible to the rural population. It is staffed mainly by Auxiliary Nurse Midwives (ANMs) and supervised by Lady Health Visitors (LHVs). Although the ANM is responsible for pre- and post-natal care, immunizations, and family planning services, it is generally felt that the sub-center is a neglected unit. The Population Centre of Lucknow in 1978 undertook a study of the function of sub-centers and the ANMs. A total of 102 sub-centers was sampled through a 2-stage stratification of the 6 project districts of the India Population Project. The main findings are that younger and unmarried ANMs tend to work in more remote, less accessible sub-centers. Only 55% of the ANMs interviewed said that they received guidelines from their LHV supervisors. On the average ANMs spend 18 days per month in the field and 11 days per month in the headquarter village. There is, however, much variation in work style, and 12% of the ANMs spend more than 25 days in the main village per month. On an average, an ANM covers 5.6 villages and 232 households per month. 20 to 30% of the ANMs reported problems in supply, accommodations, payment and security. LHVs regularly visit the sub-centers, but seldom go into the field. Although a doctor is supposed to visit the sub-center every week, one usually comes every other week instead.