This paper shows that overall Korean exports to southeast Asian countries have long-run equilibrium relationship with its determinants such as trading partners` real GDP, real exchange rates, Korean FDI to those countries, and Korean production capacity. The results are consistent to the international trade theories. According to the results, Korean exports to those countries increases in the long-run as their real GDP, real exchange rates, Korean FDI to those countries, and Korean production capacity increases. The empirical results also show that estimated coefficients of the export determinants are not common for all interesting trading partners. To say, elasticities such as income elasticities and exchange rates elasticities of Korean exports to those countries are different for each trading partner. It seems that heterogeneous coefficients of export determinants reflect the differences in industrial structure and final demand structure of trading partners.