<p>We<strong> </strong>verified the association of biosocial and academic variables to Burnout occurrence in nursing students<strong>. </strong>It is a quantitative, analytical and cross-sectional study. We applied a Form to biosocial and academic characterization and the <em>Maslach Burnout Inventory</em> in 570 nursing students between April 2011 and March 2012. Burnout occurrence is higher among students enrolled in first semester, who attend 10 disciplines, without thoughts of leaving the course and who has no job activity. The high Emotional Exhaustion and low Professional Efficacy predominate among students without work activity and with no thoughts of leaving the course. The high Cynicism predominated among students aged 20-24 years, enrolled in first semester, who does not work and without experience in healthcare. Few biosocial and academic characteristics contribute to Burnout occurrence in nursing students, raising the need of interventions to relieve stress in this population.</p><p><strong>Keywords:</strong> Nursing; Burnout, Professional; Stress, Psychological; Students, Nursing; Analytic epidemiology.</p>