The Patagonian opossum, Lestodelphys halli, is known from a few skeletons of captured animals and several isolated fragments recovered from owl pellets in Argentina. Recently, more than 300 remains (mandibles, maxillae, crania, and other bones) were found in owl pellets and associated bones, comprising the largest known collection of L. halli. A detailed morphological analysis of craniomandibular and dental variation is reported and comparisons with other small didelphids also are made. Intraspecific variation is discussed and differential diagnosis of the species is presented.