The fungus SKB-1152 bleaches oxygen-alkaline treated hard wood kraft pulp (OKP) rapidly. In the initial phase of fungal treatment, maximum production of manganese peroxidase (MnP) was observed. The filtrate from a 1-day fungal treatment could bleach OKP when manganese, glucose, and glucose oxidase were added. A possible role of MnP in the initial fungal bleaching process is suggested.