Injury and illness among youth working on farms are important problems. The types of farm tasks performed by children and the ages at which they begin these activities have not been well characterized. This cross-sectional study characterized agricultural work performed by adolescents in a rural Iowa county to better understand the patterns and extent of exposures to agricultural risk factors. This information will help to develop prevention strategies for agriculture-related injury and illnesses for children working on farms. The Keokuk County Rural Health Study is a prospective cohort study of randomly selected households in Iowa. In Round 2, all youth, aged 12 to 17 years participating in this population-based study, were asked about their use of farm machinery, work with livestock, pesticide handling, and other farm activities. The age at which they actually began these activities, the age they believed youth should start these activities, and sources of health and safety training they received were also ascertained. Adults in the study were asked the same questions about youth. Matched parental reports and opinions were compared to their children's reports and opinions using McNemar's chi-square tests. A total of 143 youth and 684 adults with farming experience completed the interviews. There were 118 pairs of parents and youth. Fifty percent of male youth, and 18 percent of females had performed agricultural work at some time in their life. Twenty-five percent of all male youth, and 5 percent of females were currently working on farms. Close to 30 percent had driven tractors, all-terrain vehicles, and pick-up trucks. Despite the legal prohibition of hazardous work by children under age 16, several younger children reported that they had driven a self-propelled combine, worked in silos, or handled and applied fertilizers in the past 12 months. Youth began riding on tractors at a mean age of 7. The mean ages for driving tractors and all-terrain vehicles were 11 and 10, respectively. The mean age for driving a self-propelled combine was 13. Children began applying or handling fertilizers at the age of 12. There were discrepancies between parent and youth reports regarding the frequencies, starting age, and opinions relative to performing agricultural tasks. These results suggest the need for implementing guidelines, particularly for age appropriate agricultural tasks.