In Europe, ticks are particularly important vectors of pathogens known as tick-borne pathogens (TBP). TBP can influence hosts, including domestic animals and humans as well as ticks. This review focuses on interactions between hard ticks and medically and veterinary significant bacterial pathogens i.e. Borrelia burgdorferi s.l., Anaplasma spp, and Rickettsia spp. The interactions between ticks and bacteria include among others the impact on gene expression and tick behaviour. Infection with TBP may influence tick salivary proteins and midgut receptors. Infection with B. burgdorferi s.l. changes the bahaviour of the tick allowing them for longer questing and increased mobility, while A. phagocytophilum increases survive in low temperatures by upregulating the expression of antifreeze glycoprotein (IAFGP). Whereas Rickettsia spp. increases ticks attraction towards the 900 MHz electromagnetic field.