The purpose of this paper is to verify the hypothesis that to reduce income disparity among people in different regions and different income classes in a developing country, it is more effective to develop industries with links to the agricultural and industrial sectors than to pursue industry sophistication. In this paper, we selected as a case study Thailand, where industries have become highly sophisticated and automotive fuels are changing from fossil fuels to biofuels. We focus mainly on the biofuel industry, and showcase agricultural product processing and food processing, the petroleum products industry, and the textile and automobile industries. In order to verify the above hypothesis, we used multipliers of a SAMI-O linked model developed based on the year 2000 version of an input-output table to demonstrate how disparity among people in different regions and different income brackets may change the current social and economic structures of Thailand if these six industries equally expanded their exports. This model is made up of an 89×89 SAM dimension with the following two features: separation of production and household factors into two regions as they are segmented, and the separation of the oil refining sector of production activities into automotive fuels and other fuels, and further separation of automotive fuels into gasoline, ethanol, diesel and biodiesel. We obtained the following test results through inter-industry comparison of these six industries. First, spillover effects were found to be exerted on overall sectors including production activities, labor, capital and households to a larger extent by the biofuel, agrotechnical, and food processing industries, which are related to the agricultural sector, than by manufacturing industries such as textile, automobiles and petroleum products. This test result revealed that it is more effective to process agricultural products into industrial products and export them than to export industrial products such as textile products, automobiles and petroleum products. Next, the results for regional disparity demonstrated that industries related to the agricultural sector and the petroleum products industry reduce regional disparity, whereas the textile and automobile industries increase it. The biofuel industry has a greater effect on reducing regional disparity than any other industry in both the labor and capital sectors. Finally, the results covering disparity among people in different income brackets showed that the petroleum product industry exerts little impact on disparity among people in different income brackets, whereas the biofuel industry reduces disparity. However, this effect is no more than 1/2 or 1/3 of the effect exerted by the agrotechnical or food processing industries. Meanwhile, the textile and automobile industries widen this disparity. These findings verify the hypothesis that it is effective to develop industries with links to agricultural and industrial sectors to reduce income disparity in a developing country. As described, the industrialization model, which developing countries have adopted to achieve economic development, have not reduced disparity among people in different regions or in difference income brackets, rather the disparities have widened. In addition, the results demonstrate that disparity among people in different regions and different income brackets can be reduced more by export of biofuels, processed upland field crops and processed agribusiness products than export of products from the manufacturing sectors. JEL classification: Q15, R15, R58