Eight hundred and two sera of owned dogs from four small towns north-west of Bologna were examined for the presence of antibodies against Coxiella burnetii and Leishmania infantum. At the same time, 149 sera of 69 dog owners from the same area were tested for the presence of antibodies to Q fever, leishmaniasis, echinococcosis/hydatidosis and toxocarosis. Of the 802 dog sera, 7 (0.87%) were positive for Q fever. Of the 69 dog owners, 24 (35%) were positive for Q fever, 4 (6%) for echinococcosis/hydatidosis and 3 (4%) for toxocarosis. Some epidemiological evaluations are made on the possible role played by the dog in spreading the zoonoses considered, at least in the area examined.