To date, Wrinkle-lipped Bat (Chaerephon plicatus) is the only species of the family Molossidae in Vietnam. It is found throughout much of Asia but rarely recorded in the country. Every published record of this species ftom Vietnam was only resulted ftom a single individual with little data on morphology. Particularly, the previous publications did not include any information about either colony size or roosting site of the species within Vietnam. Between 2001 and 2014, a series offield surveys was conducted throughout the country with an intensive search for ftee-tailed bat species. The obtained results indicate that Wrinkle-lipped Bat is a widespread bat species but its known roosting sites in Vietnam are quite distjunct. Its colony size is in both seasonal and geographical variations ranging ftom several hundreds to over three million individuals. The species inhabits seasonally and permanently in northern and southern regions, respectively. This paper provides taxonomic and ecological assessments with an emphasis on morphological measurements, colony size, roosting habitats and national distributional range of Wrinkle-lipped Bat within Vietnam.