Incidence rates of injury related to farm machinery were estimated for Athens County, Ohio, using data generated as part of the National Electronic Injury Surveillance System (NEISS) of the Consumer Product Safety Commission. The study period was 1980 through 1985. The service area of the principal hospital in the county, which participates in NEISS, closely approximates the population of the county. The population of the entire county and the rural farm population, based on US Census data, were used as denominators in calculation of rates. There were 147 injuries related to farm machinery over a six-year period, 14 of which were coded as occupational. One hundred twelve (84.2%) of these injury victims were men. The annual incidence rate per 1,000 rural farm resident population was 25.6 per 1,000 for children under the age of 14 years and was 55.6 per 1,000 for adults age 25 to 34 years. Annual rates for adults age 35 and up ranged from 13 to 19 per 1,000 rural farm residents. The annual number of tractor rollover injuries decreased during this study period, while the annual numbers of other tractor injuries did not change. Hospital emergency department visits can be used to document the need for and to evaluate injury prevention measures.