X-ray diffraction, optical- and scanning-electron metallographic and microhardness studies have been conducted in pure Ni and a Ni-base alloy (HASTELLOY Alloy C-276) in an effort to determine if hydrides form in the alloy during cathodic charging in the presence of a strong H-recombination poison. The studies indicate that hydrides do form and that the extent of surface damage caused by them is a function of the alloy thermomechanical state. In the annealed alloy, hydrides produce a network of crystallographic cracks. In the 50 pct cold-worked alloy, extensive intergranular blistering and lamellar peeling are observed in addition to the crack network. In the cold-worked and aged alloy, damage similar to, but less extensive than, that of the cold-worked alloy is found. The average depth of damage penetration may be accounted for by the bulk diffusion of H in the alloy. It is not clear whether the observed susceptibility of the cold-worked and aged alloy to H embrittlement can be attributed to hydride formation.