Uniquely among theropods, "Ceratosaurus" possessed small, elongated, and irregularly formed osteoderms (skin bones) along the midline of its body. Such osteoderms have been found above the neural spines of cervical vertebrae 4 and 5, as well as caudal vertebrae 4 to 10, and probably formed a continuous row that might have extended from the base of the skull to most of the tail. As suggested by Gilmore in 1920, their position in the rock matrix likely reflects their exact position in the living animal. The osteoderms above the tail were found separated from the neural spines by to , possibly accounting for skin and muscles present in between, while those of the neck were much closer to the neural spines. Apart from the body midline, the skin contained additional osteoderms, as indicated by a by large, roughly quadrangular plate found together with the holotype; the position of this plate on the body is unknown. Specimen UMNH VP 5278 was also found with a number of osteoderms, which have been described as amorphous in shape. Although most of these were found at most 5 m apart from the skeleton, they were not directly associated with any vertebrae, unlike in the "C. nasicornis" holotype, so their original position on the body cannot be inferred from this specimen.