The pigments of D . spathularia separated into 5 bands when chromatographed on a column of magnesia and diatomaceous earth. The pigment in the lower band was tentatively identified as B -carotene. The cells of D. spathularia were gray to white when cultured in darkness and yellow when cultur-ed in white light from fluorescent lamps. Cultures grown in darkness became pigmented when transferred to light. Dark-grown cells were killed when exposed to direct sunlight in the presence of air, whereas under the same conditions in an atmosphere of N greater survival occurred. Light-grown colored cells were not killed when exposed to direct sunlight in air. Similar results were obtained when cells were exposed to light from a Mazda AH4 lamp. There was a close positive correlation between the pigment content and the percentage surviving exposure to sunlight. It was concluded that carotenoid pigments protect the cells of this fungus from photodynamic injury.