This article describes the development of the portfolio assessment technique as a strategy for teacher education at university level, in order to create a positive relationship between humans and environment. It shows the theorist approach and the research process used to validate the ground hypothesis. As a result, we found that this strategy stimulates the capacity for self-evaluation, empowers students to act responsibly towards the environment, and helps them develop skills for applying environmental knowledge, even though the performance of the students that participated on the experimental design had no statistic significance. Furthermore, it describes a specific experience in order to facilitate the implementation of the strategy by university faculty in any discipline. Environmental Education, Assessment Portfolios, College Education.