Heavy metal pollution in the port area had affected aquatic organisms. The research about the heavy metal content of ballast water of commercial vessels, both passenger or cargo vessels, berthing in Port of Tanjung Emas Semarang (PTES), has been conducted by using method of AAS (Atomic Absorption Spectroscopy). Sample was gathered from vessels berthed in PTES, dated on December 18th 2014 to October 21st 2015. Results of the research show that the mean content of Pb in ballast water tank is 0.37192 mg.l-1. Based on the Decree of Minister of Environment Number 51/2004, the heavy metal content of Pb in ballast water tank has exceeded the quality standards of port waters.