One of the main factors affecting ship resistance is navigation in shallow water ways. Ship frictional and wave making resistance change during shallow water entrance. The speed of navigation in shallow water and water depth are prominent factors in ship shallow water resistance and ship sinkage and dynamic trim can effects the resistance too. The relation between ship resistance and these factors in shallow waters is so complicated. Therefore it is so hard to derive a theoretical formula for ship resistance in shallow water. Moreover the relations reported in literature for ship resistance in shallow water can be used in just the cases that no sinkage and dynamic trim is occurred. The model test in towing tank is a well-known method to evaluate the ship resistance in shallow waters. In this paper facilities to study the ship resistance have been prepared. A model of 35000 tons product carrier have been used and shallow water tests have been conducted in towing tank of Sharif University of Technology for different approach speeds and water depths. The drag force exerted on the model and dynamic trim and sinkage have been measured and the results are analyzed. A relation has been derived on the basis of experimental results to evaluate the ship resistance in shallow water when the trim and sinkage are significant. According to results there is a special forward speed for each water depth that the ship resistance is lower. Entering the shallow water with these forward speeds can reduce the fuel consumption in the waterway.