The harmonization of testing procedures for fuel cell stacks is of importance in order to reach comparable and reliable data of the characteristics. Within a European project "Development of PEM Fuel Cell Stack Reference Test Procedures for Industry" (StackTest) harmonized and industrially relevant testing procedures have been developed. An approach for testing methods is described with the aim to determine the influence of different parameters on the performance of a low temperature PEMFC stack. Changes of the parameters were the stack temperature, the anode and cathode stoichiometry and the anode and cathode humidity, which have, besides the gas pressures, a major impact on the stack performance. The stack performance was evaluated using the variation at different electrical load values. Additionally, two polarization curves at different parameter settings were performed. (C) 2015 Elsevier B.V. All rights reserved.