In present study the zoonotic role of cat in Bartonella henselae transmission have determined. It has done on 100 cats in 2 groups: indoor and outdoor and in 2 age's subgroups. Bartonella henselae was not isolated from blood culture of cats. 23 cats from 100 cats (23%) had antibodies against B. henselae. In this study there were no significant differences statistically in seroprevalence between cats and their owners (p<0.381). Seroprevalence of cat owners was 18% and in control group (persons who own no cat) was 5%. There were significant differences (p<0.004) between cat owners and control group. Only 6 cats of 50 cats under 6 months old had antibodies to bartonella henselae, and in the other group 17 cats were seropositive and there were significant differences between these two groups (p<0.009) that showed seroprevalence in cats more than 6 months old is higher than the cats under 6 months old. 2 indoor cats from 50 indoor cats and 21 outdoor cats from 50 outdoor cats were seropositive and comparing of these two groups showed significant differences (p<0.OOO5), which confirmed indoor cats are less frequently infected than outdoor or stray cats.