Small rodent species are the most important blood source of tick larvae; their role is crucial for tick survival, maintainance and spread in nature. From data of 1409 ticks collected from 282 individuals of three small rodent species live-trapped at a natural habitat, we drew conclusions about aggregation of ticks, the anatomical sites most frequently used for engorgement, different susceptibility of host species to tick infestation. We studied data of various age and sex groups of hosts, individuals of different reproductive status and recaptured rodents. The tick load of A. agrarius and A. flavicollis differed significantly, accumulation of ticks was shown on the auricles of both Apodemus species, and on the throat-neck region of A. agrarius. Old rodents carried more, lactating females less ticks, than the average. Data of recaptured hosts showed, that ticks invade the body via the toes and nose and they are aiming for the auricles. Voles were significantly more heavily infested with nymphs which fed in the auditory tracts, which were free of ticks in mice. The phenomenon of aggregation is important for understanding the ecology of tick-borne diseases, as only a minority of the hosts are responsible for disease risks, and it is particularly important for control strategies that apply acaricides to reservoir hosts.