In this study, a performance analysis of the Cathode Catalyst Layer (CL) of a Proton Exchange Membrane fuel cell (PEMFC) is investigated under various operating temperature, pressure and saturation levels. Recently, we performed a parametric study of the cathode catalyst layer structural parameters on the performance of a PEM fuel cell, in which the cell operating conditions were taken fixed. The catalyst layer has been computed using a macro-homogenous model. Same model has been used here and influences of the operating conditions such as temperature, pressure and saturation degrees are considered. Amongst the operating parameters affecting the CL performance, the saturation level(s) is the most influencing parameter. Computations show that reduction of s from 75 to 25%, improves the CL performance by 30%. The mathematical model assumes homogeneous and steady-state conditions, and consists of equations that include the effects of oxygen diffusion, electrochemical reaction rates, and transport of protons and electrons through the ionomer (polymer electrolyte) and solid phases. The CL consists of four phases: ionomer, solid substrate, catalyst particles and void spaces. The void spaces are assumed to be either fully flooded by liquid water, partially flooded or un-flooded at all. Computations show excellent agreement with the literature. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.