An irreversible light‐enhanced degradation has been observed in amorphous silicon solar cells exposed to intense illumination (50 suns) at elevated temperature (≳130 °C). Unlike the light‐induced degradation observed at lower temperatures, the light‐enhanced degradation observed at elevated temperatures is not reversed by annealing and it not suppressed by a strong reverse bias. An analysis of the time decay of the short‐wavelength spectral response at various temperatures indicates that the degradation mechanism is associated with the diffusion of hydrogen at elevated temperatures both in the dark and under intense illumination. ©1996 American Institute of Physics.