Abstract: A numerical study is made of the dynamics of the circulation that arises from forcing by a steady, uniform longshore wind in the Persian Gulf. The three-dimensional hydrodynamic model (COHERENS) has been employed to drive upwelling in the Northern part of the Persian Gulf. Atmospheric forces as well as tidal force have been employed in this model. Total simulation times, run in a fully prognostic mode are 11 years, which is sufficient to develop a steady state seasonal cycle of circulation and water mass properties in the Persian Gulf. Findings of the model suggested that a seasonal thermocline is evident with a surface to bottom temperature difference of around 12°C in summer. Simulated results show that when the direction of upwelling-favorable wind is parallel to the coast in the Northern part of the Gulf with a speed of greater than 9 m sec-1, upwelling occurs. A minimum of 4 days continual wind parallel to the coast is required to cause upwelling in this region. It is also found that the coastal sea surface temperature is a very good indicator of upwelling at the study area. The model predictions of coastal circulation and vertical temperature structure are compared with the limited available observations.