We report on fleas collected from small mammals in two forests, a lowland semideciduous dipterocarp forest and a highland evergreen forest, in southern Viet Nam. In the lowland forest, only one species of flea (Xenopsylla vexabilis Jordan) infested a single species of rodent [Berylmys berdmorei (Blyth)]. In the highland forest, seven species of fleas were collected from eight species of small mammals. Three species of fleas, Lentistivalius insolli (Traub), Lentistivalius occidentayunnanus Li, Xie & Gong, and Gryphopsylla jacobsoni (Jordan & Rothschild), collected from mammals in the highland forest represent new records for Viet Nam.