The long-toothed pipistrelle (Hypsugo dolichodon) was recently described as a new bat species based on four specimens from Laos and Vietnam. During investigations of taxa in the Vespertilionini tribe, we noted that specimens reported as Falsistrellus affinis (recently transferred to genus Hypsugo) from Myanmar and Cambodia have mtDNA sequences and craniodental characteristics similar to H. dolichodon and different from genuine H. affinis. Mitochondrial homogeneity within H. dolichodon was also apparent as there was no nucleotide difference between the widely distributed Cambodian, Lao and Vietnamese specimens in CO1 or Cytb genes. Although ecological data are scarce, H. dolichodon appears to be a cave-dweller which would suggest that conservation measures are a priority because tropical caves are under high pressure from human use.