The prevalence of Coxiella burnetii and Chlamydia psittaci antibodies was investigated in 530 dog specimens divided into six groups, i. e. A = private watch dogs, B1 = service dogs from Bratislava, B2 = service dogs from other localities of Slovakia and Moravia, C = watch dogs from farms, I = household dogs, T = stray dogs. The dogs demonstrated the higher seropositivity to C. burnetii (11.7%) than to Ch. psittaci (5.5%). The highest percentage of antibodies to C. burnetii was found in stray dogs (23.7%), less prevalence of antibodies was observed in the animals in group C (13.6%), almost the same positivity was proved in the dogs of group B1 and B2 (10.5 and 10.6%). The highest positivity to Ch. psittaci was demonstrated in the dogs of group A (8.7%), less in group B2 (6.6%) and the least number in group B1 (1.9%). The stray dogs occupied the intermediate position in this data (Tab. I). Ninety four localities were tested, from which 38 were seropositive. Neither acute coxiellosis nor chlamydiosis were proved in any animals examined. Ninety per cent of dogs were found healthy, but 10% of dogs demonstrated hepatopathia and gastroenteritis. Two of them (category A and I) were seropositive to C. burnetii (titer 1:8 to 1:16) and one to Ch. psittaci (titer 1:16). Both C. burnetii and Ch. psittaci attack dogs parallely with the agents of other zoonoses, of which the most common is Toxoplasma gondii (Tab. II). Several dogs demonstrated seropositivity to three up to five zoonotic agents (Tab. III).