The colombian armed conflict started more than fifty years ago and continues to exist. However, the ACR (Colombian Agency for Reintegration) guides the reintegration into civilian life of those who have demobilized from illegal armed groups. Psychosocial professionals are the agents who have greater contact with the veterans and experience high levels of burnout (Aguirre & Novoa-Gomez, 2011). This investigation pretended to analyze burnout on six psychosocial professionals from a behavioral analytical perspective, in order to assess whether an intervention designed to strengthen repertoires of psychological flexibility, had a favorable effect on the decrease of the syndrome. For this reason, a within series single case design was followed and instruments were used as the Attitude Towards Work Questionnaire (Esparza, Guerra y Martinez, 1995), the Acceptance and Action Questionnaire (Barraca, 2004), ACT Hexaflex (Wilson, 2006), self-reports and clinical case formulations (Munoz & Novoa-Gomez, 2010). The results of functional analysis reveals burnout as an experiential avoidance pattern, likewise, is evident a favorable effect of ACT in this people.