The California Chemistry Diagnostic Test (CCDT) was developed by chemistry faculties at the University of California, California State University, and California Community College systems to address dissatisfaction with existing chemistry assessment instruments. The instrument was tested at 25 campuses of the 3 systems, after which Glendale Community College (GCC) undertook a project to validate the test locally by comparing test scores with students' final grades. The validation procedure examined the test's content-related and criterion-related validity, reliability, disproportionate impact and bias, and cut scores. For the systemwide validation, a comparison of test scores and final chemistry grades for 4,023 students showed a Pearson correlation coefficient of .42, exceeding the minimum standard of .35 established by the Office of the Chancellor. The local validation at GCC included 228 students and also resulted in a coefficient of .42, indicating that the CCDT score was a significant predictor of chemistry performance. The test was also found to have a high reliability in both the statewide and the local validations. With respect to test bias, while both the statewide and local validations found small but statistically significant differences for gender and ethnic groups; the differences were considered to be too small, however, to be attributable to the instrument. (A definition of terms and suggested cut scores are included.) (KP)