A new riffle beetle is described and figured based on an exceptionally well-preserved individual preserved in Upper Cretaceous amber from northern Myanmar. Cretohypsilara parva gen. et sp. nov. is undoubtedly placed in the extant beetle family Elmidae, not assigned to a precise subfamily, though it represents the first record of a fossil riffle beetle possessing characteristics of the subfamily Larainae, including elongate subovate body covered with dense pubescence, clubbed antennae, and exposed protrochantins. It represents the oldest definitive record for the family, based on genitalic morphology, long claws, and the distinctive expanded prosternum. This Cretaceous riffle beetle is also probably a true water beetle, living in running water, providing information about the poorly known aquatic beetle fauna in the Mesozoic. (C) 2018 Elsevier Ltd. All rights reserved.