Background and Objective: Hydatidosis is one of the most important zoonoses caused by larval stage of Echinococcus granulosous which is distributed worldwide. Determination of the parasite genotypes in relation to the host specificity and transmission routes is of great importance. So far, DNA based analysis of the isolates obtained from different host species has lead to identification of 10 different genotypes (G1-G10) in the world endemic areas. This work was designed to identify the genotypes of the hydatid cysts isolated from domestic animals and people in Zanjan. Materials and Methods: A total of 86 isolates, including 49 sheep, 28 cattle isolates collected from the slaughter houses, and 9 human isolates collected from hospitals were subjected to genotype analysis using PCR-RFLP of the ribosomal DNA ITS1 region. Results: A fragment of about 1000 bp was amplified from all samples using ITS1 PCR. The endonuclease digestion of the PCR products resulted in the RFLP pattern that were the same for all isolates as the pattern expected for the sheep strain. The restriction patterns of all 4 enzymes used ( Alu I, TaqI, RsaI, and Msp I), consistently approved the same genotype. Conclusion: The PCR RFLP pattern obtained from our samples were characterizes as E. granulosous sensu stricto, which is the same as what has been previously reported in Iran. It can be concluded that the hydatid cyst isolates in our study area, Zanjan, is basically similar to that of other endemic areas of Iran.