During the decomposition of sodium pentachlorophenolate by Alcaligenes eutrophus, Aeromonas hydrophila var. hydrophila and var. anaerogenes, Azotobacter chroococcum, Azotobacter vinelandii, Flavobacterium aquatile, Pseudomonas fluorescens, Cytophaga johnsonae, Corynebacterium aquaticum, Brevibacterium testaceum, and Arthrobacter globiformis the following were identified as metabolites: pentachlorophenol acetate, pentachloroanisole, 2,3,4,5-tetrachloroanisole, 2,3,4,6-tetrachloroanisole, 2,3,5,6-tetrachloroanisole, 2,3,4,5-tetrachlorophenol, 2,3,5,6- tetrachlorophenol, tetrachlororesorcinol, tetrachlorohydroquinone, and tetrachlorocatechol diacetate, the principal metabolite being pentachlorophenol acetate. Up to 6.2% of the sodium pentachlorophenolate used was recovered as pentachlorophenol acetate, while all other metabolites were found in amounts less than 1% of the starting compound.