This study aims to explore how 4th-grade students dealt with evidence and theory by analyzing their journal entries for a science inquiry activity. It was found that they understand science practices, which was evident from their claims in their science journals. The 4th graders took a science class and worked with self-directed inquiry using the Korean science elementary textbook. After the inquiry activities, they completed science journals that included their test question, data, and claims regarding their inquiry. To characterize types of coordination between evidence and theory, the journals were analyzed. Twenty-one 4th graders took the course, and they finished five science inquiries and wrote summaries in the journal at the end of each inquiry. A total of ninety-one students’ journals were collected and analyzed for this study. Based on the analyses, five types of coordination between evidence and theory were found. The most frequent type was students proposing inquiry questions based on what they already learned and trying to confirm it through the inquiry activity. It was followed by a discussion regarding the direction of elementary school’s science inquiry activities as well.