To understand the epidemiology of tick infestation and tick-borne diseases in pet dogs in south-eastern China and to develop a reference for their prevention and treatment, we collected 1550 ticks parasitizing 562 dogs in 122 veterinary clinics from 20 cities of south-eastern China. Dogs were tested for common tick-borne pathogens; collected ticks were identified and processed for the detection of tick-borne pathogens. The use of an in vitro ELISA diagnostic kit for antibody detection (SNAP®4Dx® Plus) on dog sera found the infection rates with Borrelia burgdorferi sensu lato, Ehrlichia canis, and Anaplasma spp. to be 0.4%, 1.3% and 2.7%, respectively. By using a specific ELISA method, the infection rate with Babesia gibsoni was 3.9%. Rhipicephalus sanguineus sensu lato, Haemaphysalis longicornis and Rhipicephalus haemaphysaloides were the major tick species identified on pet dogs. PCR tests were conducted to detect five tick-borne pathogens in 617 ticks. The infection rate was 10.2% for E. canis, 3.4% for Anaplasma platys, 2.3% for B. gibsoni, 0.3% for B. burgdorferi s.l. and 0% for Babesia canis. Some ticks were co-infected with two (1.46%) or three pathogens (0.16%). These results indicate the infestation of pet dogs by ticks infected with tick-borne pathogens in south-eastern China, and the need for effective treatment and routine prevention of tick infestations in dogs.