Background: Dicrocoeliasis is caused by digenean trematode of Dicrocoelium dendriticum, small liver fluke, a hepatic parasitic disease in ruminants and human, throughout the world. D. dendriticum infection has been considered to be correlated with the economic and veterinary aspects. Objectives: The aim of the present study was to determine the prevalence and intensity of infection with D. dendriticum in sheep and cattle in Guilan, Mazandaran and Golestan provinces from Caspian Sea Littoral, Northern part of Iran. Methods: For this purpose, 4 cities in every province, 4 villages in each city, and 4 districts in each village were chosen for sampling. Totally, 1344 faecal samples of sheep and cattle were examined. It should be taken in to consideration that the number of eggs per gram of feces (E.P.G) was determined by flotation technique. Results: The results suggested that sheep was infected 4-5 times more than cattle in all three provinces. The average of prevalence of D. dendriticum infection in sheep and cattle were 38.43% and 9.37%, respectively in Guilan province. The average of prevalence in Mazandaran province was determined to be 21.35% and 4.16% in sheep and cattle, respectively. It is worth noting that the highest infection rates were occurred in Chalus and Noor from Mazandaran province. The average of D. dendriticum infection was determined to be 6.87% in sheep and 1.87% in cattle from Golestan province. Conclusions: Our results indicated that not only the prevalence but also the intensity of infection were higher in sheep compared to cattle Furthermore, the rate of infection was about two fold higher in both hosts from Guilan province. Therefore, according to the higher prevalence of infection in two provinces of Guilan and Mazandaran and the importance of sheep in distribution of infection, sever control program are required by providing comprehensive plans.