The implementation of the value of life and integrity has been done in the teaching and learning process of science by moral problems in life that relate to biological issues and to train the students' capability in problem-solving. It stimulated the students' moral development involving logic, feeling, and behaviors deemed as right and wrong in students. The purpose of this study is to describe the students' tiers of moral development through valid and reliable biological problem-solving. This study is descriptive research with a qualitative approach. The theoretical formulation formed is a design of the level of moral development about biological problems. The collection of data is done through a task-based interview. The subject of this research is students in the 8th grade of Banjarmasin Middle School. The data is analyzed using a constant comparison method. The results of this study indicate a valid and reliable level of students' moral development in solving biological problems. JPM2B1: An action is considered good from its principles and point of view to fulfill his/her obligations and needs without caring about other people's needs. Students often claim that "solving a problem is easy, it's because our teacher taught us to solve it". JPM2B2: An action is considered good from its perspective and principle of the movement for the greater good and planning a solution. JPM2B3: An action is considered good with a view of helping each other in creating a better future. JPM2B4: An action is considered good with a view of caring for the needs of others, emphasizing rational considerations for humanitarian reasons and God's blessing.