Reading strategies are plans for solving problems encountered during reading while learners are deeply engage with the text. So, comprehension is not a simple decoding of symbols, but a complex multidimensional process in which the leaner draws on previous schemata applying strategies consciously. In fact, metacognitive strategies are accessible versatile vehicles if the readers are aware and cognizant of their applications. This paper studied the most frequent used strategies by Iranian ESP students. Fifty six students completed 30-item questionnaire of MARSI (2002). It included three strategy categories: Problem Solving strategies (PROB), Global Reading strategies (GLOB), and Support strategies (SUP). Results indicated that students at the highest level perceived PROB strategies up to 58.93%, SUP strategies up to 32.14%, and GLOB strategies up to 30.37%. Ranking the individual strategies represented that the highest used strategies are strategy 8 (overall mean= 3.51), strategy 20 (overall mean=3.52) and strategy 11 (overall mean=3.77). Keywords: ESP, Metacognitive strategies, Problem Solving strategies, Global Reading strategies, Support strategies