. This study aims to identify the use of Augmented Reality in facilitating changes of students' conceptual representation in endocrine system and enhance students' comprehension to the concepts. The method used in this study is Quasi-experimental with the design Non equivalent control group design. The samples in this study are consisted of 30 students that use AR in learning and 30 students that use learning video. The instrument used in this study is an essay test about conceptual representation and multiple choice test about concept mastery. The conceptual representation test result shows that students in the experimental class use more diverse modes of representation changes with text, diagram, combination of text-diagram, text-picture, and diagram-picture after the learning with AR. The majority of students in the experimental class also use a combined macroscopic-microscopic-submicroscopic level of representation with better concept depth and accuracy than students in the control class. The experimental class students achieved higher concept mastery for the C3 and C4 levels. The results of this study indicates that learning by using AR can facilitate changes in conceptual representation and mastery of students' concepts in the endocrine system.