ABSTRACT The purpose of this study was to revise "Cornell Critical Thinking Test, Level Z "(CCT-Z) used for evaluating, selecting and teaching college students in Taiwan. "The revised Cornell Critical Thinking Test, Level Z" (RCCT-Z) includes 34 items, which most college students can complete in 40 minutes. A group of 1803 college students from 7 colleges & universities were sampled. Analysis of reliability indicated that the revised test had reasonably high internal consistency (.61 & .79) and stability (.45 & .68). The concurrent validity of this revised test was supported by correlation with Watson-Glasser Critical Thinking Test. Three related studies were conducted by analyzing the total population with T-test for 3 specific categories: M/F, students who had and had not studied logic, and attendance in public/privite college/university. Data from each supported the hypotheses, futher inferring the validity of the revised test. Percentile Rank Norms were developed for the total population and for categories.