The main objective of this study was to gauge preparedness in math with achievement in first semester math for the fall 2005 intake of Manufacturing Sciences Division post-secondary program students. The data used to measure this level of preparedness was gleaned from students' high school Grade 12 (new and old curriculum) or Ontario Academic Credit (OAC) math marks and the results of a diagnostic test given to students during the first week of the fall semester. In addition, success in first semester math was analyzed in relation to the specific high school math course taken. The findings of this study demonstrate that high school math marks alone are a poor predictor of performance in first semester math. In addition, students emerging from the new curriculum Grade 12 Math for College and Apprenticeship (MAP4C) failed first semester math at nearly three times the rate of all other course groupings combined. Conversely, students emerging from any of the university stream high school Grade 12 math courses or the college stream Math for Technology (MCT4C) were best prepared for college math in Manufacturing Sciences Division post-secondary programs. The diagnostic test marks were not a reliable predictor of individual student success (or "at risk" behaviour) in first semester. However, students falling into the fortieth percentile or lower groupings on the test showed a marked increase in tendency towards "at risk" behaviour or failure. Technician stream students as a group exhibited a failure rate that was double that of the technology stream group. It is recommended that the administration of the diagnostic test be continued by the college and that tracking of these indicators be carried out annually in order to monitor these trends. In addition, it is recommended that students at the high school level are made aware of the need to take Grade 12 Math for Technology (MCT4C) as a minimum preparation for success in Manufacturing Sciences Division math courses. The questions raised in this study concerning differences in performance according to gender and stream warrant further study. (Contains 3 tables and 10 figures.)