To determine the prevalence of animal fascioliasis in coastal regions of the Caspian Sea, during 2006-
2007, a total of 2368 faecal samples were collected from sheep (n=1250), cattle (n=975) and horse (n=143). The samples were obtained directly from the rectum of animals. Floatation method was performed for determination of egg per gram of faeces (EPG). Our findings revealed the presence of Fasciola spp. eggs in 9.53, 7.8 and 2.5% of sheep and 32.5, 12.1 and 3.1% of cattle in Gilan, Mazandaran and Golestan,
respectively. Among the horse faecal samples collected from Golestan and Gilan provinces, no eggs were
found in Golestan, while 50% of those of Gilan were infected with Fasciola spp. Cattle was one of the most
infected animals in the studied areas. A positive correlation was found between climatic conditions and
animal fascioliasis. Among different meteorological factors, rainfall seems to be the strongest factor.