This study attempts to find out if reading proficiency level in EGP affects reading performance and use of reading strategies in ESP. Sixty seven Iranian tertiary level students received from two general English classes were selected randomly and given a reading comprehension test battery in EGP and based on the mean score they were classified into two groups of low and high reading proficiency levels. Then, they were given reading test in ESP followed by strategy questionnaire for reading specific materials. Analysis of data evinced the amount of ESP reading strategy use is the same in high or low level of EGP reading proficiency but ESP reading score is significantly more in the high group. It is concluded that the process and product aspects of ESP reading follow different patterns considering in mind the EGP reading proficiency background of ESP students. Students with different proficiency levels in EGP reading might process an ESP text similarly but perform on it differently indicating that ESP reading ability is not necessarily short circuited by knowing how to read (in ESP or even in EGP), but by other factors such as EGP reading ability (as was examined in this study), motivation to read, attitude toward reading, knowledge of their discipline, etc. Therefore, ESP teachers should not feel over concerned about the process of reading and consider other aspects in their students when they come from the EGP to the ESP course.
