The objective of this study was to apply a new conceptual approach to the study of pediatric farm injuries. A large case series of pediatric farm injuries in North America was evaluated to assess interactions between risk factors for injury. Information about pediatric farm injuries to children in three age groups (<6 years, 6-12 years, 13+ years) was coded with respect to children's behavior (did unexpected child behavior contribute to injury?), predictability of injury risk (based on what the child had been doing, was the nature or occurrence of injury unexpected?), environmental events (did unexpected environmental events contribute to injury?), and level of environmental risk (low, high). The reliability of coding between independent raters was excellent (kappa=.83) for the 330 cases providing complete data. Results revealed that, in high-risk environments, unexpected child behavior was coded more frequently when children under 6 years were injured than for older children, whereas in low-risk environments unexpected child behavior had less impact on injury risk and showed no such age variation. With increasing age, the predictability of injury increased in a high-risk context, suggesting that youth engage in increasingly hazardous activities as they develop. Consistent with this interpretation, unexpected environmental events increasingly contributed to injury in a high-risk context in the oldest age groups. The observed variations in risk factors suggest that interactions between behavioral and environmental factors are important to consider in studies of the etiology of pediatric farm injuries.