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In economic literature especially in international economic literature, the Harberger, Laursen and Metzler (HLM) effect is an important issue. According to HLM effect, deterioration in the terms of trade decreases GNP and then causes deterioration in the current account. The main idea of this study is the examination of HLM effect in Economy of Iran. We use annual data of current account, terms of trade and GNP as relevant variables. In this paper ARDL approach was applied for period (1978 -2010). The Banerjee, Dolado and Mastre and also Pessaran and shin cointegration test verified the equilibrium long run relation between our variables. In the other words the results of econometric estimation indicated a long run relationship between current account, terms of trade and GNP. According to these results, terms of trade and GNP have direct effects on current account.