In Brazil a career must be chosen early, and this causes a lot of psychological problems, what calls for investigation in this area. This work aims to evaluate the influence of the career guidance process on the development of maturity to make a career decision in adolescents that participated in a career guidance service. Sixty-three subjects have participated in this study, both male and female, between 15 and 19 years old, coming from public (N=27) and private (N=36) schools. The Maturity Scale for Professional Choice (EMEP) was used as an evaluation tool before and after career guidance. EMEP is a multi-factorial scale with five sub-scales: Determination, Responsibility, Independence, Self-knowledge, and Knowledge of Reality. The findings of the two tests, were statistically compared with the Student's T test and the Wilcoxon non-parametrical test (p<0.05) for the data with not normal distribution. The total results of the samples showed significant dimension differences in Determination, Self-knowledge, Knowledge of Reality, and Independence, indicating development in the participants' maturity for career choice.