Thomas described this Mindoro rat with glossy dark-brown fur flecked with orange and yellowish sides. It is endemic to Mindoro, where a 1998 survey listed the species among the local endemics recorded in its secondary lowland-forest study area.
Thomas’s original account describes smooth, glossy fur: dark brown with orange flecks above, yellowish sides, and whitish to dirty slate-gray underparts.
In 1998, two sites in Mt. Iglit-Baco National Park were described as patches of secondary lowland rainforest. Rattus mindorensis was listed among Mindoro endemics recorded in the study, but the article does not identify the particular patch where it was found.
An extinction-risk assessment has not been added yet.