This study explored the relationship between EFL learners’ vocabulary size, lexical coverage of the text and reading comprehension texts (narrative & argumentative genres). To this end, 120 male and female out of 180 students studying at Talesh Azad University were selected based on their performance on the Nelson Proficiency Test. A Nelson reading proficiency test was also administered in order to check the homogeneity of the learners in their reading proficiency. After that, the researcher administered reading comprehension tests with narrative and argumentative genres in order to find the lexical coverage and vocabulary size for such reading tests. Learners' Vocabulary size was measured by the Levels Test, while their lexical coverage was measured by the newest version of Vocabulary Profile. In order to probe any significant relationship between the variables of the study, Pearson Correlationwas run. Results of the study showed that there was a strong relationship among vocabulary size, text coverage, and reading comprehension test at different genres.
