One of the least intrested subjects by the student in Organic Chemistry is the stereochemistry and organic reactions. Problems encountered are too difficult for students to understand the synthesis concept including stereochemistry, and organic reaction mechanism. The impact of this problem is the luck understanding to organic chemistry. So, we need a way to overcome this problem in order to increase the quality of learning processes, through implementation of lesson study (LS). Lesson study department based Programs conducted with collaboration lecturer in the department involved at the time of plan, do, and see. The results of the implementation of LS on the stereochemistry of this learning was found to increase the quality of learning with the indicator increased mastery of the material and learning process improvement, and the positive response of students. Key word: Lesson study, stereochemistry, organic reaction, the quality of learning, reciprocal teaching strategies-antithesis