The main objective of this study was to assess the effectiveness of an intervention program for the primary prevention of negative attitudes towards immigration and the promotion of favorable attitudes towards outsiders. At the end, it analyzed the repercussions of the intervention. In the study, participated 98 students (43 boys and 55 girls) with an average age of 13.15 years (+/- 1.12). A pre-experimental design of a single group was used with pre-test and post-test measurements. The five-week intervention started with a phase of awareness about the migratory phenomenon and, on a second phase, it was proposed to develop an initiative of social impact, which culminated in the preparation and implementation of the event "Project for Peace", a meeting space between different educational centers, clubs and one NGO. In the preparations, cooperative learning projects were developed through original didactic resources. Initial results showed a prevalence of favorable attitudes about adverse beliefs. Among the favorable arguments shined the cultural discourse and the main prejudice was the economic consequences. After the intervention proposed by this study, was clearly noted an improvement of the positive attitudes. The main changes refer to the economic-labor dimension. No differences were found in the negative scale, confirming the tendency to stability of prejudices. It is of interest to enrich the curriculum with transformative experiences towards an educational change that transcends the academic level and brings benefits in the social field.