The main objective of this study is to determine whether the Diagnostic test can be used to precdict students performance subsequent in tests and First Semester Examinations. A minor objective is to compare their mathematical achievements during SPM 1994/95 to the First Semester Examinations. A minor objective is to compare their mathematical achievements during SPM 1994/95 to the First Semester Examinations result and also to review their achievements in the Diagnostic test. The sample consist of 116 students (first year 1995/96) from Faculty of Science in University Technology Malaysia. The analitical methods used were correlation analysis, regression analysis and other appropriate statistical discriptive methods. In conclusion, the results showed the existence of a significant relationship between students knowledge in mathematics to their subsequent achievement at a higher level. (Tiada abstrak dalam versi B.Malaysia.)