Chasmogenus is a Neotropical genus of water scavenger beetles belonging to the family Hydrophilidae.

[1] The genus Chasmogenus was described for the first time by David Sharp in 1882 for species from Guatemala and Panama.

[1] Currently, a total of 36 species is identified and documented, most of them recorded from the Guiana Shield Region.

Small size (2.5–5.0 mm), bearing a clearly visible sutural stria; long maxillary palps; metafemora usually densely covered by hydrofuge pubescence.

By the presence of the sutural stria, in the Neotropical region, Chasmogenus can only be confused with some members of the genus Primocerus.