It is a well-documented finding that high school students in schools across the nation, including California, fail to achieve at the proficient level in mathematics, based on standardized test scores. The purpose of this research study was to compare the findings of students taught using traditional instructional methodologies versus cooperative learning methodologies. The study was conducted in four ninth grade Algebra I classes on a South Los Angeles high school campus, which has 1,700 students. Of the student population, 110 students participated in the study. The researcher utilized descriptive statistical analysis as a means to review previous student standardized test scores to determine baseline performance. After the treatment, a district adopted assessment was administered and used as a post-test to gather quantitative data to compare the scores of students who were taught using cooperative learning methodologies versus those who were taught using traditional methodologies in Algebra I. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]