The infection of food animals to hydatid cyst is a concern from economic and public health stand points. In this survey, the prevalence of hydatid cysts was studied in 547 buffaloes slaughtered at the slaughterhouse in Urmia. Samples from 58 cases (10. 6%) were infected to hydatid cysts. The infection rates of lung and liver were 45 cases (77. 5%) and 37 cases (63. 7%), respectively, while each heart and kidney samples, 1 case (1. 7%) was found infected. Also, 24 buffaloes (41. 3%) were infected both in lung and liver. However, none of the buffaloes studied had the spleen infected to hydatid cyst. The maximum cysts in the infected lungs and livers were 52 and 81, respectively. The minimum cysts in lungs and livers was 1. The average numbers cysts in the infected lungs and livers were number of 5. 11 and 3. 87, respectively In the only case, related to heart and kidney, there were 1 and 2 cysts respectively. Considering the prevalence rate, the results obtained from the statistical analysis did not show any significant difference between male and female sexes, whereas a significant statistical relation was observed between the age of buffaloes and the prevalence rate (p<0. 05). The age group above 5 years showed the highest level of infection. In this survey, there was no significant difference in the intensity of infection to hydatid cysts in males comparing to that of females. But a significant difference was found between the intensity of infection in age groups below 2. 5 years and the ones above 5 years (p<0. 05). In conclusion, the results revealed high infection to hydatid cyst in Iranian buffaloes, so more attention of related control organizations seems to be needed.