In this paper, we propose a unique co-generation system including a biomass boiler-using a thermoelectric generator (TEG). The boiler burned biomass fuel derived from a cow dung. In this system, warm water is generated through heat exchange in the boiler, and electricity is generated through the TEG that uses the high temperature of an exhaust gas from the boiler. In this study, the co-generation system was not well optimized, with the result that both the heat exchange efficiency of the biomass boiler and hence, — the amount of electric power generated were very low. However, the study demonstrated that the co-generation system that using the biomass as a heat source, and a TEG as an electric power generator can provide an effective energy source.