Phrasal verbs (PVs) are one of the most challenging areas in language learning for EFL learners. These items are one of the essential parts of lexicon since they are very frequently used by the native speakers and using them is a real test of fluency for non-native learners. The present study aimed at examining the impact of proficiency level and topic on the use of PVs. It also tried to investigate the individual frequency of PVs in the Louvain Corpus of Native English Essays (LOCNESS) and Persian Gulf university learners' corpus (PerGULC) and whether there is any difference between the uses of PVs among these two corpora. Forty three EFL students participated in this study. The students' proficiency level was assessed by Oxford Placement Test. Afterwards the students were asked to write essays on three different topics, "a letter to one of your family members", "censorship agree or disagree" and "imagination and reality in the modern world". The writing of Iranian EFL learners and native speakers were tagged by Stanford Tagger and the frequency list of PVs was made by AntConc software. The statistical test results indicated that the proficiency level and topic did not influence the use of PVs significantly among Iranian EFL learners. It was also revealed that the frequency of individual PVs was different in LOCNESS and PerGULC and Iranian EFL learners underused PVs significantly. These findings suggest using corpora in EFL classes and also teaching PVs based on their frequency and importance not at random.