This study aims to improve the science learning outcomes of fifth grade students of Tlogosono Elementary School through the application of the Problem Based Learning (PBL) method on the material of Our Earth Structure. The background of this study is the low learning outcomes of students on the material which is characterized by a lack of understanding of concepts and active participation in learning. This study is a Classroom Action Research (CAR) which is carried out in two cycles. The research subjects were 11 students, consisting of 8 male students and 3 female students in the 2024/2025 Academic Year. This study uses the Independent Curriculum as a learning reference. The Problem Based Learning method is applied with the following stages: (1) problem orientation, (2) student organization, (3) independent investigation, (4) development and presentation of results, and (5) analysis and evaluation of the problem-solving process. The instruments used in data collection include observation, interviews, learning outcome tests, and documentation. The results of the study show that the application of the PBL method can significantly improve students' science learning outcomes. There was an increase in the average class value from cycle I to cycle II, as well as an increase in learning activities and student involvement during the learning process. Thus, the PBL method has proven effective in improving science learning outcomes on the material of earth structure in grade V of Tlogosono State Elementary School