Avian influenza viruses (AIV) are a highly contagious disease with economic and public health impact that belongs to the Orthomyxoviridae family. Wild migratory waterbirds are known as the main reservoirs of AVI which can distribute viruses to poultry and humans. Considering that Neor Lake, located in the southeast of Ardabil, is the habitat of migratory waterbirds from the countries around the region, there is a risk of transmission and distribution of influenza viruses from wild migratory birds. The present study aimed to monitor the seroprevalence of AI virus H5, H7, and H9 subtypes in migratory waterbirds of Neor Lake, Ardabil, northwest of Iran. A total of 101 blood samples were randomly collected from seven migratory bird species. HI, test was carried out on sera based on OIE protocol to detect H5, H7, and H9 subtypes. In this study, H5N2 and H7N1 antigens were used for the detection H5 and H7 subtypes, respectively. Suspicious samples on the first test were re-examined with H5N1 and H7N7 antigens. H9N2 antigen was used for the detection H9. Results of the tests performed on sera were negative for H5N1, H5N2, H7N1 and H7N7 viruses. Overall, 11.89 % of birds were seropositive for the H9N2 virus. The highest seroprevalence of the H9N2 virus was in Mallard (25 %) and the lowest seroprevalence was in Whooper swan (10.5 %). In this survey, despite seronegative evidence against H5 and H7 of subtypes, because of the prevalence of high pathogenic avian influenza (HPAI) viruses in countries of the region and some areas of Iran, it is recommended to periodically implement surveillance and control programs such as monitoring of circulating AIV in migratory waterbirds of Neor Lake.