A study on bionomics of scrub typhus vector and its host species was conducted in a transmigration scheme of Kumpeh, Jambi, Sumatera. Ten species of trombiculid mites were collected from 6 species of rats and 2 species of squirrels. Leptotrombidium (L.) deliense, a known vectorof scrub typhus vector elsewhere, was found mostly on Rattus tiomanicus. This rat species was widely distributed in forest, disturbed land and cultivated land habitations found in the study area. Chigger infestations on R. tiomanicus trapped in disturbed land were 63.6% — 81.8%. The average number of chigger collected from disturbed land was highest in December, from forest habitation was in October and from the cultivated land habitation was in November. Rattus tiomanicus was found to be a potential rat species for maintaining the natural cycle of scrub typhus in the study area.