This paper covers the results of an action research project stemming from the necessity of change in the climate of coexistence within a primary school in Barcelona. The investigation purpose was to give an answer to this action hypothesis: ¿How can the work of social and citizen competence contribute to the prevention and peaceful resolution of the conflicts from the physical education area? To achieve this, once the initial state of the students data was collected an action strategy for tutoring sessions and physical education was implemented. The strategy was developed by the teachers who participated in the work group with the aim to promote in the pupils the acquisition of skills of social and citizen competence to encourage prevention and peaceful conflict resolution. Qualitative and quantitative data were collected throughout the implementation using questionnaires, participant observation and systematic observation. Improvements of relational processes were shown in the obtained results. Towards the end of the intervention the predominant responses facing conflicts were either ignoring the fact or starting dialogue. As for the conflict resolution, those which entailed violence were minimized and on the other hand peer mediation and autonomous dialogue were significantly increased.