Proton exchange membrane fuel cells (PEMFC) are attractive alternative source of electricity. The current study involves the computational fluid dynamics simulations of PEMFC under isothermal and non-isothermal conditions to investigate the performance of fuel cell. Effect of pressure and temperature on fuel cell performance is studied under non-isothermal conditions. PEMFC is modeled at 323 K and 1 atm under isothermal conditions whereas under non-isothermal conditions, the simulation is run on 353 K and 3 atm. The results show that the current density increases with increase in operating pressure of PEMFC and vice-versa with operating temperature. © 2018 Institute of Physics Publishing. All rights reserved.