Jiyong Lee. 2022. A Study on Machine Translation Aspects of Korean Cause and Reason Connection Grammar and Expression Items: Focusing on Kakaoi, Google, and Papago Translator. Studies in Modern Grammar 115, 207-226. Along with the 4th Industrial Revolution, the era of artificial intelligence has arrived. Artificial intelligence technology is already actively being used in many areas that were considered to be areas that only humans could do. A representative example of this situation is an artificial intelligence-based translator. As time goes by, it is obvious that a high-performance translator will be developed. However, it is time to discuss how translators can be used for learning foreign languages. Therefore, this study aims to examine how the items presented as similar grammar items in Korean language education are calculated in the artificial intelligence translator. Korean similar grammar items are one of the most difficult for teachers and learners in the field of Korean grammar education. This is because grammar items with similar functions exist in various forms. This study aims to analyze how equivalent grammar items that perform these similar functions are realized through machine translation. The results presented in three types of translators are compared, and furthermore, the accuracy is determined by using the reverse translation method. Based on these research contents, it is expected that it is possible to think about the parts to be supplemented in machine translation and the parts to be considered when using them in Korean language education.