Ticks are known as vectors of a wide range of pathogens of medical and veterinary importance; some of them of zoonotic concern constitute a hazard for the emergence of tick-borne diseases shared between humans and domestic animals and becoming a part of the ‘One Health’ concept. Canine and feline tick-borne diseases have emerged in recent years, performing an extensive geographic distribution and enlarged global prevalence. The present review focuses on the recent epidemiological studies on the emergence of tick-borne bacterial pathogens in dogs and cats, and the discussion whether pet ownership increases the risk of tick-borne diseases. A lot of data provide confirmation that dogs and cats themselves may substantially contribute to the circulation of the ticks and tick-borne bacterial pathogens in the environment. Molecular diagnostics of tick-borne pathogens infections generates a lot of problems like the choice of molecular methods and molecular markers for the detection of bacterial genomic DNA, but play an important role in the diagnosis of infections. The study provides some insight into molecular diagnostic techniques and new potentially recognized bacterial pathogens of this group. Protecting human and companion animal health from vector-borne infections requires controlling vector populations, containing development of novel, practicable strategies that will limit vectors and transmission of vector-borne disease pathogens.