This paper provides a cost-efficient business mix and principles of regulation for the Kaohsiung Harbor Bureau. The authors use a multi-product model that represents port operations with three variables: mooring, stevedoring, and warehousing. A Fourier cost function is used to calculate several cost indicators. The sample covers monthly data in 1997-2001. By analyzing the cost indicators obtained, it is found that both individual operations and all of the operations together as a whole exhibit significant economies of scale and scope. Moreover, the presence of excess capacity in stevedoring and warehousing have been detected, as well as a presence of cost complement between mooring and stevedoring. Port operations cannot improve economic efficiency with perfect competition. On the contrary, the government should design economically reasonable regulations. Because port operations can not improve economic efficiency by market mechanism, port operations should be regulated by a proper authority in order to effectuate maximum social welfare.