This study investigated the comparative effectiveness of teaching through the use of interactive multimedia and conventional teaching method in biology on senior high school students concerning students' achievement.The pretest-posttest non-equivalent quasi-experimental design was used for this study. One hundred and ten (110) form three (Form 3) General Science students who had Biology as an Elective subject were selected for the study. They were grouped and labeled control and experimental groups. Students in the experimental group were taught through the use of interactive multimedia whereas the control group was taught through the traditional teaching approach. The study found that both methods were quite effective for teaching Photosynthesis in Biology. However, out of the two methods, the multimedia approach was found more suitable for teaching abstract topics. The study also reported no statistically significant differences in the students' academic performance by gender. These findings suggest that the academic achievements of students in Biology can be improved with multimedia instruction. The study recommends that the computer should be used to complement the teachers' teaching but should not take over the teaching process. A similar study could be carried out in a similar environment but should include more than one topic as this study used only one topic.