It was proved that transmission of some pathogens may occur between infected and uninfected ticks co-feeding on a host in the absence of systemic infection. The effect was studied of co-feeding of two different tick species Ixodes ricinus and Dermacentor reticulatus on the course of the non-parasitic stage. Species chosen for the experiment may share their habitats and co-infest animals in nature. In the course of the study the process of egg maturation, oviposition and larval hatching were investigated. In order to estimate if co-feeding influence can counteract host immunity, three subsequent infestations of rabbits were analyzed. Mono-specific groups values of such a parameters as egg amount, number of eggs per 1 mg of female engorgement weight, female oviposition weight loss, hatching success were higher in inter-specific groups were compared. The results indicate that co-feeding with other tick species may partially reduce the influence of host resistance in subsequent infestation.