The study examined the effectiveness of BEEP Cards (BioEnergetics Enhancement Play Cards) on students' conceptual understanding of bioenergetics. The study involved one group of grade 11 students (n=29) from a public secondary school in the Philippines. The study employed a mixed-method research design, utilizing both quantitative and qualitative data to answer the research questions. Specifically, a one-group pretest-posttest action research design was used in this study. The study used a six-week exposure to the use of BEEP Cards. The quantitative data were obtained from a researcher-made and expert-validated 25item pre- and post-test questionnaire while the qualitative data were secured from focus-group discussions. Dependent samples t-test was used to determine significant differences in students' conceptual understanding of the topic Bioenergetics. Findings revealed a significant difference in the students' conceptual understanding before and after six-week exposure to BEEP Cards. Additionally, responses from focus group discussions imply the effectiveness of BEEP Cards in enhancing students' conceptual understanding. Hence, the utilization of BEEP Cards was found to help enhance students' conceptual understanding and performance in Bioenergetics among the Grade 11 students in a public senior high school in Valenzuela City.