Ornithodoros mimon Kohls et al. is an argasid tick, originally described from larvae collected on bats from Bolivia and Uruguay. In Brazil the species is aggressive to humans and animals. Nymphs and adults of O. mimon were collected from the roof of a residence in Araraquara, São Paulo, Brazil, whose residents were bitten by ticks. Once in the laboratory, they were fed on rabbits and maintained in biological oxygen demand incubator at 27 ± 1 °C and 90 ± 10 % relative humidity. The females, after mating, laid eggs that resulted in larvae that were identified by the original description and also by the paratypes examination (RML 50271-50274) deposited at the United State National Tick Collection, Georgia, GA, USA. The life cycle of this species was obtained through the acquisition of two generations of ticks (F1 and F2) in the laboratory using rodents and rabbits as hosts. The biological parameters of larva, nymph and adult stages of both generations were recorded from infestations of the laboratory hosts. Larvae showed a profile of feeding for days on the host, whereas the nymphs and adults fed only for few minutes. First nymphal instar (N1) molted to second nymphal instar (N2) without blood meal. The species life cycle was elucidated for the first time.