This paper studies the influence of the operating variables (glycerol concentration, temperature and feed rate) for a direct glycerol fuel cell fed with glycerol using polybenzimidazole (PBI) impregnated with KOH as electrolyte and Pt/C as catalyst. Temperature displays a beneficial effect up to 75 °C due to the enhanced conductivity and kinetics of the electrochemical reactions. The optimum cell feed corresponds to 1 mol L-1 glycerol and 4 mol L-1 KOH, supplying sufficient quantities of fuel and electrolyte without massive crossover nor mass transfer limitations. The feed rate increases the performance up to a limit of 2 mL min-1, high enough to guarantee the access of the glycerol and the exit of the products. Finally, the use of binary catalysts (PtRu/C and Pt3Sn/C) is beneficial for increasing the cell performance. © 2014 Sociedade Brasileira de Quimica.