Three attempts to use ticks of the genus Ornithodoros as a medium for importing from foreign countries disease agents of which they are not known to be normal hosts or vectors have been successful. The diseases, the tick species, and the minimum intervals between the ingesting of blood of infected guinea pigs by the ticks and the subsequent recovery of the disease agents from them were as follows: Tobia petechial fever, O. rudis, 11 days and 53 days; S. African tick-bite fever, O. moubata, 36 days; spring-summer encephalitis, O. moubata, 40 days. The recoveries were not made by tick bite but by injecting guinea pigs with saline suspensions of the tick tissues in the case of the rickettsial diseases and a broth suspension in the case of spring-summer encephalitis.