In this paper, the longshore sediment transport in littoral zones is investigated. For investigation of sediment transport in the nearshore zone, the effects of waves, currents and topographical conditions of the coast, are considered. Linear wave theory is used for investigation of wave behavior. Governing equations of littoral current are continuity and momentum, and for calculating the concentration profile of suspended sediments at depth, convection-diffusion equation must be solved. A computer program called “PLSTP” (Prediction of Littoral Sediment Transport Program) is developed for investigation of sediment transport process in littoral zones. The finite difference method is used for solving the governing equations. The results show a good agreement between this model and existing measurements.