[영문]To evaluate a theory-based educational program to prevent Lyme disease and other tick-borne illnesses (TBI), a randomized controlled trial of an educational program was delivered to ferry passengers traveling to an endemic area in southeastern Massachusetts. Rates of TBI and precautionary and tick check behaviors were measured over three summers in 30,164 passengers. There were lower rates of TBI among participants receiving TBI education compared with control participants receiving bicycle safety education (relative risk [RR] = 0.79) and a 60% reduction in risk among those receiving TBI education who visited Nantucket Island for more than 2 weeks compared to control participants (RR = 0.41, 95% confidence intervals = 0.18 to 0.95, p qqqlt; .038). TBI-educated participants were also significantly more likely to take precautions (use repellent, protective clothing, limit time in tick areas) and check themselves for ticks. The study demonstrates that a theory-based Lyme disease prevention program can increase precautionary behavior and result in a significant reduction in TBI.