Optimized robust control for Polymer Electrolyte Membrane Fuel Cell (PEMFC) air-feed systems is an important challenge in improving the net fuel cell power output in automotive applications. This paper focuses on the practical implementation and performance comparison of robust and adaptive Second Order Sliding Mode Controllers (SOSMC) for this application. Both controllers aim to minimize the power consumption of the air-feed system by operating it to maintain the optimal oxygen excess ratio in the fuel cell. The controllers have been tested using a Hardware-In-Loop test bench based on a commercial twin screw compressor and 90 Cell, 33 kW fuel cell emulator. The experimental results demonstrate the effectiveness of both controllers and highlight that the adaptive controller is more power-efficient as the adaptive gains further reduce the internal power consumption of the air-feed system. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.