In a cross-sectional study, a total of 5381 slaughtered animals, namely 928 cattle, 243 buffaloes, 3765 sheep and 445 goats were inspected macroscopically for hydatid cysts in northwest Iran, with prevalence values of 38.3%, 11.9%, 74.4% and 20%, respectively, being recorded. Prevalences were higher in females compared with males, but a significant difference (P < 0.001) was only found in sheep and cattle. Most cases which were condemned were seen in the lungs of sheep (13.4%) indicating that sheep are the most important intermediate hosts for Echinococcus granulosus in this area.