Lee, Jeonghyun. 2019. The interaction among vocabulary, ability to draw inference and reading comprehension by Korean EFL learners. Language Information 28. 40-62.The main purpose of this study was to investigate the effectiveness of vocabulary knowledge on the learners’ reading comprehension of the Korean EFL students. This study has been carried out upon the hypothesis that there is a significant relationship among vocabulary, ability to infer and reading comprehension skills. After the pre-test designed to choose the target group, twenty six participants selected as intermediate level were required to take Test I and II. Test I, where twenty words are underlined in the passage, aims to reveal correlational relationship between vocabulary and reading comprehension ability. The result showed that there is correlational relationship. Test II intends to reveal the relationship among vocabulary knowledge, ability to infer and reading comprehension. To this end, twenty words were provided in the blank form in the reading passage and participants were asked to select the correct answers describing the meaning of passages. Although those words were not exposed in the test, students with high score in pre-test got higher score in Test II in general. This result implies that indirect vocabulary learning strategy is effective for enhancing reading comprehension and ability to draw inference. In sum, vocabulary plays a pivotal role in reading comprehension for Korean EFL students and the best way to learn new words is to direct life experiences and to expose various experiences or to read a clear context for word learning and more complex ideas.