The increase of fuel cell (FC) system efficiency requires an optimal management of all its sub-systems. This paper discusses and analyses the possibilities of the improvement of the performance of a proton exchange membrane fuel cell (PEMFC) power source via the implementation of an optimal operating design of the air management sub-system. The steady-state PEMFC operation has been taken into account. This work takes into account a numerical and mixed technique for modeling of FC sub-systems, based on moving least squares approach. In has been analyzed the opportunity of using an adjustable backpressure valve. The work proposes a numerical optimization of air management, computing the optimal speed of the compressor and the optimal throttle opening, in correlation with an imposed operating point of PEMFC system. A Constrained Optimization By Linear Approximation (COBYLA) algorithm has been implemented to solve the optimization problem. The results are useful to design the control of PEMFC system and to develop an optimal configuration of it. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.