The present study is an attempt to investigate the relationship between cohesive readability of expository texts and reading comprehension in EFL students with different proficiency levels. One hundred students formed the participant of this study. They were undergraduate students majoring in English at University of Isfahan. To collect the relevant data, participants were divided into three groups of low proficient, intermediate and high proficient based on their scores on an OPT proficiency test. A series of expository reading comprehension tests were prepared and their cohesive readability was measured through related programs. They were divided into two groups of authentic and manipulated texts, with the cohesive readability of manipulated texts reduced. The participants answered the related tests in one session. As a result of data analysis, the findings indicated that manipulation, i.e. cohesive readability reduction has a direct impact on the students' performance in reading expository texts. It was further revealed that text manipulation, i.e. reduction of cohesive readability, was more influential on the intermediate group, i.e. positive relationship between the students’ proficiency level and their reading comprehension of expository texts with different cohesive readability levels.
