The burnout syndrome constitutes a process which bears high prevalence and important consequences among sanitary professionals, particularly among nurses. Therefore, the authors have proposed to study the three dimensions of this syndrome, namely emotional tiredness, depersonalization and lack of a sense of achievement plus the function certain personal, labor, and institutional factors have in development of this process. The authors carried out a transversal study based on a random sample from among all the nursing staff at a Madrid hospital. Two methods to gather information were employed: one questionnaire gathered sociodemographic data, labor and institutional variables while the Maslach Burnout Inventory (MBI), in its verified Spanish version, studied the three burnout syndrome dimensions. The authors made a multiple logistical regression analysis, using as dependent variables the three syndrome scales and adjusting parameters for all the other variables. Clear risk factors were shown; these included unfavorable opinions professionals hold regarding institutional variables; the scale for emotional tiredness warrants special note.