Abstract In the past few years, several cross-disciplinary corpus-based studies have been carried out on the frequency and coverage of 570 word families from Coxhead's (2000) academic word list (AWL). Some reported high coverage of this word list in their corpuses while some others questioned its generality and stated that this word list is far from complete. Hence, along with these studies, the present study attempted to examine the word frequency and text coverage of AWL on 80 research articles (RAs) written in English with 320310 running words across two Asian EFL and ESP journals. Using frequency and range as the criteria for word form selection, this study identified 438 words as the academic words and 144 new added academic words to the list which was called revised academic word list (RAWL). Applying both AWL and RAWL into the entire corpus, results support high coverage and importance of academic words in both ESP and EFL RAs. However, when two word lists were examined into ESP corpus (ESPC) and EFL corpus (EFLC) separately, academic words had higher coverage in ESPC than EFLC. From these findings it is concluded that (1) academic words play an important role in academic texts; therefore, acquisition of them seems to be essential for language learners and users, (2) because of the nature of ESP articles, ESPC holds higher coverage of academic words, (3) some of the words included in the AWL are field-specific and (4) direct attention to these words from behalf of the material and syllabus designers and teachers can lead to a better understanding of these words;hence, students’ development in their writing and reading.