The coat is composed of short, coarse hairs. The upper parts are blackish fawn, and the underparts are dull buffy white. The head is nearly black. The arms and legs are grayish, and the hands and feet are brown, becoming white on the digits.
Hexagonal scales show through the scantily haired tail.
Anisomys has small ears, strong scansorial feet, and a long tail. The great toe has a broad nail. Females have six mammae. The lower incisor teeth are laterally compressed and bladelike and are less than half the width of the upper incisors. The molar teeth are remarkably small, the length of the toothrow in a given specimen being less than half that of a specimen of Uromys with the same external measurements.