Background: Studies show conflicting evidence on the association of age and occupational injury in agriculture, and few studies have addressed the effect of age on work-related chronic conditions or preventive practices among farmers. Methods: We examined the probability of injury, work-related stress, musculoskeletal symptoms (MSS), and preventive practices for MSS as a function of aging using surveillance data of 7,711 farm and ranch operators in the central United States. Findings: Segmented regression analyses of men (85% of sample) indicated that the probability of all four outcomes increased up to a certain age and then decreased; the changepoints in years of age being 59.6 for injury, 55.4 for work-related stress, 59.6 for MSS, and 67.9 for MSS preventive practices. Female operators had an increasing trend for stress up to age 29.7, while they showed no changepoints across their age spectrum in the proportion of injury, MSS, and prevention techniques. Conclusion/Application to Practice: These findings emphasize the need for preventive efforts particularly among younger and middle-aged farmers and ranchers, and the need to modify work duties to match work abilities at older ages.