Abstract: The study developed and validated a computer-aided instructional material in Elementary Algebra. It made used of Quasi - Experimental Research method utilizing one group pretest-posttest design. It also utilized the 100 items validated pretest/posttest developed for the purpose of attaining the objective of the study. The subjects of the study were the 15 randomly selected students in Elementary Algebra at Peter Pan Learning Center, Baras, Rizal, Philippines. Findings revealed that the performance pretest and posttest of the subjects in both Algebraic expressions and first degree equation and inequalities are satisfactory and very satisfactory respectively. It emphasizes that the computed-aided instructional materials in Elementary Algebra brought significant gain in knowledge and skills of the students upon its exposures.