The present study has tested on a sample of 315 employees of the University of Seville (193 faculty and 122 non-faculty) a structural model of the mediating role of personal perceived competence in the appearance of burnout syndrome and stress symptoms under stressful work conditions. The evaluating instruments used were: a sociodemographic questionnaire, the Maslach Burnout Inventory, the Occupational Stress Scale and the Magallanes Stress Scale. Bivariate correlation matrixes and structural equation modeling were used to analyze the data. The estimated models for each group were satisfactorily adjusted, thus ascertaining the mediating effect of perceived competence over the dimensions of the syndromes depersonalization and personal accomplishment, and stress symptoms. Its mediating effect was not confirmed for the emotional exhaustion dimension, which acted as mediating variable. Furthermore, it was determined that cognitive-aptitudinal components acquire more strength in the estimated model used for faculty whereas for non-faculty, those of emotional characteristics do.