Electric field‐enhanced degradation has been observed in amorphous silicon solar cells exposed to intense illumination (45–60 suns) at elevated temperatures (≳160 °C). The front tin oxide contacts of both p–i–n and n–i–p cells darken significantly when a strong reverse bias is applied at elevated temperatures and under intense illumination. Compositional profiles of the cells show that a strong reverse bias causes a depletion of hydrogen near the contacts. These results are interpreted in terms of proton motion near the p/i interface of p–i–n cells and negative hydrogen ion motion near the i/n interface.