Room temperature electron irradiation of as-grown n-type CdS at 250 keV (between the sulfur and cadmium displacement thresholds) and at 1 MeV (above both displacement thresholds) produces ad increase in the concentration of shallow donors but little change in the concentration of net acceptors. The increase in majority carrier concentration due to irradiation is observed to recover almost completely in an annealing stage centered at 250°C. A reverse annealing occurs from 300-400°C followed by a recovery from 400-400°C. These last two stages also occur in unirradiated samples and are attributed to surface effects induced by high temperature annealing.