This study of the relationships between mathematical ability and success and retention in a general chemistry course was conducted at an open-enrollment university whose mission is to provide a quality education to a culturally and economically diverse student body. We studied the correlation between the demonstrated level of mathematical ability and success in chemistry and the correlation between the demonstrated level of mathematical ability and retention in chemistry. After the chemistry department implemented a mathematics prerequisite for the chemistry course, data were examined to compare success and retention prior to and after the adoption of the prerequisite. Analysis showed that success and retention in chemistry increased after the adoption of the mathematics prerequisite. (Contains 3 tables and 6 figures.)