Using strategic intervention materials (SIM) in Science class is essential for achieving students' needed competencies, which they could have succeeded in regular classroom instruction. This study examines the retention of concepts among Grade 11 learners in Central Philippines after exposure to teacher-made Strategic Intervention Materials (SIMs). It utilized the Quasi-Experimental Research Design, Post-test Post-Post-Test, Experimental Group only design. To determin0e the significant difference in the level of proficiency right after and a semester after exposure to SIMs intervention Wilcoxon signed-rank test for paired samples was employed. Results showed that the SIMs helped students exceed the core knowledge, skills, and understanding requirements. Learning is best transferred through authentic performance tasks which made retention of Science concepts evident.0