This thesis is a study of the cost and return on investment in sunflower seeds production in 1986/87. The data for the analysis was obtained by using questionnaires to interview farmers from Amphoe Pattananikom in Lopburi Province. The data used in this analysis was classified into three categories based on the farm sizes; small scale farms of 1-5 rai, medium scale farms of 6-10 rai and large scale farms of more than 10 rai. The results of the study showed that the average cost of production of small, medium and large scale farms were 959.89, 879.15 and 776.19 Baht per rai, respectively. Furthermore, the return on investment, which were analysed by various methods, can be concluded as follows: from the revenue-expense status analysis and economic term analysis, investment in large scale farms gave the highest return. For example, the ratio of total expenses on total revenues was 0.96 and the rate of return on cost of production was 4.26%. In addition, the large scale farms provided the lowest selling price and lowest quantity of production at the break-even point. From the study, the break-even price per kilogram was 4.80 Baht and at the selling price of 5.00 Baht per kilogram, break-even production was 134.16 kilograms per rai. However, the study, when analysed by means of farm investment analysis and farm management analysis, showed the highest return on investment for small scale farms. Certain important problems discovered from the studies are: high costs of production due to expensive seeds and fertilizer, inadequate knowledge of agricultural technologies which causes low productivities and substandard quality of products. There is also a lot of competition in the vegetable oil market and selling prices are low compared to the cost of production. Some suggestions for solving the problems are as follows: Government Authorities dealing with agricultural extension should make studies and tests to develop high productivity seeds with immunity to diseases. They also should study and test about cultural practices, taking care of sunflowers, especially in pest and disease problems. Furthermore, the government authorities should co-operate with private organizations to provide the farmers with adequate knowledge about agricultural technologies to increase productivities per rai and to improve the quality of products. In addition, they should promote the use of sunflower production not only in vegetable oil industries but also in margarine, soap, paints and varnish industries and finally they should encourage animal feed industries to use local residual of sunflower seeds.
