is investigated. to this purpose, Revealed Comparative Advantage (RCA) Index is calculated based on Agricultural and total economy export, separately, then forecasted by using Auto- Regressive Integrated Moving Average (ARIMA) approached, for 2008-2013. The results show that considering both commodity baskets, Turkey and Iran had comparative advantage in Pistachio export in 1982-2007, but U.S did not. Also, forecasting RCA index, based on both commodity baskets, show the improvement of U.S Pistachio export situation, unlike the values of RCA index forecasting for Iran and Turkey is falling. Therefore, it is recommended that Iran and Turkey attempt to identify new consumer markets in order to retain their market shares in pistachio export. Following the U.S imposed policies during last six years which improved its pistachio export, Iran and Turkey can increase their market shares.