This study aimed at comparing the psychometric properties of three measures of burnout administered in 320 Greek primary school teachers, namely the Maslach Burnout Inventory (Maslach and Jackson 1982), the Burnout Measure (Pines and Aronson 1988) and the Copenhagen Burnout Inventory (Kristensen et al. 2005). Confirmatory factor analysis tested a three-factor solution for each inventory, consistent to the respective theory. Results yielded a reasonably good model fit for the MBI, and merely acceptable model fit for the BM and the CBI. Overall the findings suggest that the MBI is more appropriate instrument for assessing teachers' burnout compared to the MB and the CBI, which presented not so well-defined inner structure and highly correlated subscales.