The effect of a surface nickel alloying layer on moisture-induced embrittlement of Ni-3(Si, Ti) alloys has been investigated by tensile tests at room temperature, using nickel-deposited materials. Undeposited Ni-3(Si,Ti) alloy became remarkably embrittled in air. However, nickel-deposited Ni-3(Si, Ti) alloy showed a high elongation value, indicating the suppression of embrittlement caused by hydrogen decomposed from moisture in the air. When the surface nickel alloying layer consists of fc c(gamma) solid solution with a high nickel concentration and good adhesion to the substrate, improvement of tensile elongation is the greatest. The results have been discussed from the chemical and structural viewpoints of the surface nickel alloying layer.