This Fourth Annual Report summarizes accomplishments of the Agricultural Sector Analysis Project in Thailand during fiscal year 1977 and relates these accomplishments to past work progress as well as to projected work for fiscal year 1978. Accomplishments described in this report are a result of the cooperative research effort being carried out by the Division of Agricultural Economics (DAE) of the Ministry of Agriculture and Cooperatives, Royal Thai Government, and the Center for Agricultural and Rural Development of Iowa State University. The cooperative research effort is funded by the United States Agency for International Development and the Royal Thai Government. This summary describes one phase of a sector analysis project being undertaken to provide models and empirical analysis which can aid development and policies for agriculture in Thailand.