This regulation establishes a tolerance for residues of the fungicide dimethomorph [(E,Z) 4-[3-(4-chlorophenyl)-3-(3,4- dimethoxyphenyl)-1-oxo-2-propenyl]morpholine] in or on potatoes. American Cyanamid Company requested this tolerance under the Federal Food, Drug and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (Pub. L. 104-170).