Simultaneous equation models of the soyabean sectors in Japan and Taiwan are developed and estimated through seemingly unrelated regressions. The models integrate domestic supply and demand for soyabeans, soyameal, and soyaoil as well as the livestock market. Based on the established models, the impacts of economic growth and policy simulations on these markets are evaluated and compared by performing dynamic simulation analyses. Growth factors had greater impacts on soyabean import demand than did policy factors, and growth impacts themselves were more significant in Taiwan than in Japan. A 10-percent currency devaluation with respect to the US dollar would only decrease soyabean import demand in Japan and Taiwan by 0.17 and 0.35 percent, respectively. A 10- percent increase in the soyabean support price would stimulate growth in domestic soyabean import plantings of 16-54 percent in Taiwan and 9.93 percent in Japan. A 10-percent increase in Taiwan's net livestock exports or a 10-percent decrease in Japan's net livestock imports would increase soyabean import demand by 0.12 and 0.48 percent, respectively. Increased demand for soyameal and a decline in demand for soyaoil were also noticed. If the profitability of soyabean crushing were improved, soyabean import demand would increase and demand for meal and oil would decrease.