Background Roll-over protective structures (ROPS) are proven to prevent fatalities from agricultural tractor overturns, accounting for more than one-third of all production agriculture-related fatalities in the United States. In 1997, there were approximately 1.2 million ROPS-retrofittable tractors in the United States. Methods A decision analysis is used to compare the health outcomes of installing ROPS on retrofittable tractors, relative to doing nothing. A cost-effectiveness analysis builds on these results to assess the costs and benefits of installing ROPS on retrofittable tractors. Results Doing nothing would result in 1,450 fatalities and 1,806 nonfatal injuries, while installing ROPS would prevent 1,176 fatalities and 957 nonfatal injuries. Installing ROPS would cost $489,373 per injury prevented. Conclusions Installing ROPS on retrofittable tractors would reduce fatalities from tractor overturns by more than 80% and nonfatal injuries by about 53%. The cost per injury prevented would be similar to that of other injury-preventing interventions. ROPS would help prevent additional injuries from falling off tractors and tractor collisions with motor vehicles.