The technique of cross‐sectional transmission electron microscopy has been applied to study the nature of the radiation damage in GaAs bombarded with 300 keV protons to total doses of 1015and 5×1015protons cm−2. The results indicate that upon annealing at temperatures of 500 °C and above, the precipitated damage becomes visible in the form of hydrogen platelets (i.e., hydrogen‐filled edge vacancy loops) on the {110} cleavage planes of GaAs.