Despite a recent surge in knowledge about U.S. hired farm workers, little is known about the health of this population. No national data are available on the size of the population, mortality or morbidity data, or on chronic health indicators. Demographic data show that these workers are mostly Mexican immigrant or migrant males, and nearly two thirds live in poverty. At least half of all current hired farm workers are undocumented. Fewer than one in five have health insurance, either through their employer or through government programs. However, programs targeting women farm workers, such as WIC or, in California, emergency MediCal, are more effective in helping them obtain needed services. The federal Migrant Health Program serves about 13% of the total of workers plus dependent family members. This paper reviews what is known in the following topical areas: (a) mortality and morbidity; (b) access to health care services; (c) control of infectious diseases; (d) maternal and child care; (e) occupational health; (f) violence; and (g) chronic health indicators. It is suggested that future research incorporate a minimal physical examination of all patients or subjects in order to establish baseline information for the population. Such information will be helpful in targeting interventions and measuring their effectiveness.