In the present study, the ignition of hydrogen-air mixtures by a stationary hot glow plug has been investigated. The ignition process was characterized by the surface temperature when ignition occurs, as well as by the location where the initial flame kernel is formed. The experimental results indicate that the ignition temperature threshold is a function of equivalence ratio whereas the ignition location is a function of the rate at which the glow plug is heated. Comparison with two-dimensional numerical simulations exhibits significant discrepancies in terms of the temperature threshold evolution with equivalence ratio. These results seem to indicate that a number of parameters, including surface temperature in-homogeneity, surface chemistry and reaction model used, could influence the ignition threshold as well as the location of ignition.