This paper examines the effect of the privatization of stevedoring services on the operational performance of Keelung Port in Taiwan. The privatization was implemented in January 1999. The mooring times of container chips, general cargo ships, bulk carriers, and grain carriers from July 1997 to December 2001 (54 months) are analyzed. The objective of the paper is to show how privatization has affected the cargo handling efficiency at the port. In order to control the work items involved in the process of ship mooring, total mooring time is divided into 8 mutually exclusive phases. It is presumed that only 3 out of the 8 phases are related to privatization directly. These phases include preparation time, actual cargo moving time, and equipment repairing time. The structural change models of the series of preparation time, actual cargo moving time, and equipment repairing time are tested by the procedure proposed by Doldado et al.(1990) after excluding the experience factor from pre-privatization. Evidence shows that stevedoring privatization's effect on management is significant while the effect on other aspects of operation is inclusive. However, the total mooring time of general cargo ships has considerably decreased since privatization. Although 34% of the decrease in mooring time is contributed by deregulation of day-time work restrictions, 12% of the decrease can be attributed to the privatization policy. In summary, the effect of the stevedoring services' privatization on the operation efficiency of Keelung Port is significant. This finding will have important implications for policy choices and establishment in the future.