Purpose: To determine the incidence, associated consequences, and potential risk factors for horse-related injuries among youth and adults residing in Midwestern agricultural households. Methods: Demographic, injury, and exposure data were collected for 1999 and 2001 among randomly selected agricultural households within a 5-state region. A causal model facilitated survey design, data analysis, and interpretation of results; directed acyclic graphs guided multivariate modeling. Findings: From 7,420 households (84% response of eligible), involving 32,601 persons, 5,045 total injury events were reported; 1,016 were animal-related injuries, of which 215 (21%) were horse-related (rate, 6.7 events per 1,000 persons per year). Seventy-seven percent (77%) required health care; comparing those under age 20 and those 20 and older, 49% and 54%, respectively, lost work time on their operation (28% and 26%, one week or more), as a result of injuries largely associated with horse riding activities (70% and 56%). Multivariate analysis for youths under age 20 indicated: increased risks in North and South Dakota, for >0 hours worked, and for having a history of prior agriculture-related injury; and decreased risks for males. For those 20 and older, increased risks were identified for a prior injury history and less than high school education. Conclusions: Horse-related injuries, primarily associated with riding activities, are a significant problem among agricultural communities, and greatly impact their operations.