A new species of the Aeolosomatidae, Aeolosoma vietnamicum sp. n., found in freshwater bodies of Vietnam, is illustrated and described. The new species differs from its congeners in the presence of specific sigmoid chaetae in the dorsal and ventral bundles of all segments, beginning from II. These chaetae are characterized by tips with two apical teeth and an additional row of three to nine distinct denticles on the concave side of the chaetaes distal part. Aeolosoma vietnamicum sp. n. also differs from closely related species in the length, pattern and number of hair chaetae per bundle.