This study tries to discover how prosocial personality influences Burnout in a sample of 442 members of professional social workers' associations in Spain, with ages ranging from twenty-four to sixty-three years, mostly women. From its results, it is concluded that prosociality acts as a protective factor against burnout, because the positive variables of prosociality (social responsibility, empathic concern, perspective taking, other-oriented moral reasoning, mutual concerns moral reasoning, self-reported altruism, prosociality factor 1 other-oriented empathy and prosociality factor 2 helping) correlate positively with the personal accomplishment of burnout and are higher in professionals without burnout, whilst personal distress is associated with emotional exhaustion and depersonalisation, predominates in professionals with burnout. The study of the relationship between both variables is original in the field of social work and it is useful to prevent burnout amongst professionals. The aim of this study is to establish the link between burnout and prosocial personality and discover how prosocial personality influences burnout. A single-group ex post facto prospective descriptive design questionnaire was created incorporating socio-demographic data, the Maslach Burnout Inventory and Penner's Prosocial Personality Battery. The study involved 442 members of professional social workers' associations in Spain, comprising 91.1 per cent women and 8.9 per cent men, with ages ranging from twenty-four to sixty-three years. The results showed that social responsibility is significantly lower and personal distress is higher in emotional exhaustion and depersonalisation, whilst the personal accomplishment variable correlates positively with the positive variables of prosociality and negatively with personal distress. Social responsibility, perspective-taking, self-reported altruism, prosociality factor 1 (other-oriented empathy) and prosociality factor 2 (helpfulness) were found to be significantly higher amongst professionals without burnout, while personal distress predominates in professionals with burnout. The study also found that personal distress and mutual concerns moral reasoning are risk factors for burnout, whilst perspective-taking is a protective factor. It was concluded that prosociality acts as a protective factor against burnout-a novel idea of great importance when developing prevention programmes to alleviate this problem amongst professionals.