The tropical rat mite, Liponyssus bacoti, was shown to harbor the Dallas M. B. strain of Coxsackie virus for as long as 16 days following an infective blood meal. Of 36 mice exposed to the bites of infected mites during this period only one mouse, which was bitten on the third day, developed Coxsackie infection. The possibility that this animal was infected by ingesting a mite rather than by being bitten by one cannot be excluded. The fact that other mice bitten on the same or closely adjacent days did not develop infection tends to suggest that such might have been the case. Limited tests with progeny from the infected mites did not indicate that transovarian passage of the virus occurred. Thus it would seem that the mite, Liponyssus bacoti, can play but a small role, if any, in the transmission of the strain of Coxsackie virus tested.