In 2007, international seaborne trade was estimated at 8.02 billion tons of goods loaded and volume increase by 4.8 percent over the previous year. Maritime transport remains the backbone of international trade with over 80 percent of world merchandise trade by volume being carried by sea. Port improvement plays a major role in reducing sea transport costs. Transport is a key sector for international trade, for regional integration and for ensuring a balanced national development. Throughout its history , due to its strategic geographical location at the crossroads of main trade routes, Iran has played a vital role in the world trade . The major ports of the country are: Imam Khomeini port which is the biggest port in Iran. Iran has good facilities in international marine transportation service. Therefore her membership in WTO in future will provide a good opportunity for her progress and development if some standards are considered. This study is an attempt to analyze the effect of joining WTO on Iranian Commercial Ports.