Super's Career Development Inventory (CDI) was adapted to Brazilian culture and applies in a sample of 1048 students of Guanabara State's high schools. Since its purpose is to observe a maturation process, the CDI was administered to the two last grades of grade school and the first two grades of high school, where the students have from seven to ten years of schooling. A test of difference of means was carried out. The differences were statistically significant between the last grade of grade school and the first grade of high school in all scales of CDI. In a breakdown by sex, the results were not very different from the total grade results. These differences must be interpreted with caution because the scores were obtained not only from different grades but also across different school systems. Only the grade school is compulsory in Brazil, so a natural selection can happen. These results did not allow the author to reach a firm conclusion about the use of CDI for Brazilian students. Some suggestions on the format of CDI's scale and on the experience provided by the schools was made. Norms provisionally established are included in the appendix. (Author)