The development of different rickettsial species (Rickettsia sibirica, R. conorii, R. acari and coxiella burnetii) in haemocytes of Alveonasus lahorensis ticks was compared by viral observations and time-lapse cine-micrography. The interaction of different rickettsial species with the haemocytes in vitro had specific characteristic features and reflected the pattern of interaction of the rickettsiae with tick cells in vivo.