A heat developable light-sensitive material having reduced fog, increased whiteness, and stability to normal room illumination comprising a support having therein or in one or more layers thereon (a) an organic silver salt, (b) a light-sensitive silver halide or a component capable of forming a light-sensitive silver halide upon reaction with the organic silver salt (a), and (c) as a reducing agent an s-triazine-2,4,6-(1H, 3H, 5H)-trione substituted with a phenol derivative (having a substituted group in at least one of the o-positions thereof with respect to the hydroxyl group) in at least one of the 1-, 3- or 5-positions.