The genus "Apomys", of which the large Mindoro forest mouse is a member, can be identified by its small size, a long tail, elongate, narrow hind feet, the presence of four abdominal mammary glands, and a large number of skull characteristics. Within this genus, the large Mindoro forest mouse has several specific identifying features, the most important of which are its very thin and short upper incisors, long lower incisors and long snout. The tail and feet are also relatively long, even within the genus "Apomys". The characteristics of the incisors are so peculiar that when Ruedas discovered the species, he initially thought he had found a new genus.