The effects of ultraviolet radiation from different sources (sunshine, carbon arc light, ultraviolet carbon arc light, and xenon light) were examined for the discoloration of dyed fabrics finished with flame retardants based on ammonium salt. Chemicals which suppress discoloration were also investigated. Metallic borates were the most effective chemicals in suppressing discoloration. In combination with ammonium salts, these compounds also significantly improved flame retardancy.