Abstract: The Diatomyidae are a distinctive rodent family of Asian distribution. The skull is characterized by hystricomorphous musculature, and the jaw is sciurognathous in momphology. The group represents a local radiation of ctenodactyloid rodents closely related to, but not a member of Hystricognathi. The fossil record first yields Diatomyidae in the Oligocene terrestrial sediments of Baluchistan, followed by younger occurrences elsewhere in the late Oligocene of southern Asia. Successive deposits of the Indian subcontinent illustrate much of what is known of the history of the family. By the late Early Miocene and Middle Miocene, Diatomyidae are also known from Thailand, China, and Japan. Thereafter, diatomyids are rare and infrequently recorded as fossils. One taxon is known from the early Late Miocene of Pakistan, and there is a possible record in the late Miocene of southern China. Although abundant where found in the oldest fossil sites, diatomyids are not numerous as fossils in later localities, except Li, Thailand. This suggests special habitat preference or bias against preservation at sites where they do occur. The known fossil record does not indicate taxonomic diversity of the group, but this may be an artifact of lack of fossilization. Survival of Diatomyidae as specialized rodents of habitat peripheral to fluvial systems is consistent with the hypothesis that the recently recognized extant Laonastes of rocky terrain in central Laos is a diatomyid.