This study aimed to assess the totalc costs and benefits of providing protective boots for farmers to prevent leptospirosis infection. For the cost-benefit estimation, 149,236 rice famers in Sa Kaeo Province, and an estimated 140-150 days' of rice farming period, were set as the population and timeframe. Disease severity was classified into 4 levels: asymptomatic, mild, moderate, and severe or fatal. The cost per unit was composed of routine service cost, and medical care cost. 1. The numbers of cases with and without the protective boots were estimated using the odds ratio divided by the infection rate with the protective boots. 2. The number of cases associated with the disease severity "asymptomatic" was estimated using the prevalence of asymptomatic infection derived from a prevalence of asymptomatic infection study. The prevalence, at mild, moderate and severe levels, was estimated using the proportions between reported cases in the epidemiological surveillance report system. 3. The total cost with the protective boot program was composed of the potective boot program cost and the treatment cost. Both are measured from the provider perspective. The per unit cost is estimated as follows: 3.1 Protective boot cost: the routine service cost was derived from the unit cost analysis of health facilities under the authority of the MOPH in 6 provinces. The medical care cost was estimated using a cost accounting method. Data was drawn from the Office of Leptospirosis Control. 3.2 Treatment cost: the routine service cost was derived from the unit cost analysis of health facilites under the authority of the MOPH in 6 provinces, in the same study used for the cost estimation of the protective boots. The medicalcare cost was estimated using an adjusted charge method. Data were drawn from 30 purposively selected sample patients hospitalized at SaKaeo Crown Prince Hospital. 4. The benefits derived from the protective boot program were money equivalents of the prevented cases and prevented deaths measured by treatment cost. This treatment cost per unit was estimated in the same way as the treatment cost per unit whenwith the protective boot program. The results showed that (1) the total cost without the protective boot program was more than 103 million Baht, for 11,620 cases with 330 deaths; (2) the total cost with the protective boot program was nearly 91 million Baht. The protective boots cost 76 million Baht. The treatment cost was 15 million Baht for 1,640 cases with 47 dealths. The net financial saving was more than 12 million Baht, for 9,980 cases with 283 deaths prevented. The results indicate that the protective boot program produces a substantial saving.However, indirect benefits, such as the reduced treatment costs and intangible costs from the patient perspective, especially the death of the patient, cannot, and have not, been calculated into money equivalents in this study are not taken into consideration. If these were so, the benefits of the protective boot program would be even more significant.