The main aim of this study was to investigate whether cooperative learning strategy would improve the learning and understanding of the topic “Human Breathing System” in Biology at Form 3. Both qualitative and quantitative data were collected during the research using checklists, classroom observation, and focus group discussion and also through assessments. Both formative and summative assessments were done in which together with the content, other skills were assessed. A focus group discussion was carried out at the end with the students to obtain their views on this new style of learning. It was seen that most students appreciated and accepted this new type of learning strategy and considered it as being beneficial to them in the learning of this topic. It was observed that cooperative learning had an impact, both academically and socially, on the students. They performed better in class and their communication skills were also enhanced. Finally, some common misconceptions were also cleared in this particular topic on using STAD as cooperative learning strategy.