5,6-Dichloro-2-benzoxazolinone, a nonphenolic compound, has been investigated as a leather fungicide. Very mildew-susceptible leather, such as vegetable-tanned sole leather, is adequately mildew proofed by about 0. 4per thousand. A smaller percentage is adequate for other types of leather. The fungicide is stable, colorless, nonvolatile, and relatively resistant to removal by leaching with water. It is a much more effective leather fungicide than 2-benzoxazolinone, which indicates that the chlorine substituents are important. Because of the known general fungitoxic activity of phenols, it might be postulated that rupture of the oxazolinone ring with production of 2-amino-4,5-dichlorophenol occurs and that the latter compound constitutes the fungitoxic substance. However, this does not seem to occur in leather, as 5, 6-dichloro-2-benzoxazolinone is very stable under acid conditions. Furthermore, 2-amino-4, 5-dichlorophenol showed no fungitoxic activity when tested in leather.