The present study has been carried out in Ashtamudi Lake, Kollam in Kerala. It is considered as a biodiversity hotspot. Wetlands are the major sites for maintaining various natural cycles and enhancing a wide range of biodiversity. The birds mainly depend on the wetland for shelter, food and also for reproduction. In the present research, avifaunal diversity of the Ashtamudi Lake was studied from three sites, such as Ashramam (S1), Prakkulam (S2) and Kandachira (S3) for the period of March to August 2019. The species diversity, evenness, richness, Sorenson's coefficient, habitat status, migratory status, ICUN status and feeding nature were analyzed. A total number of 855 birds of 33 species, under 10 orders and 18 families were recorded. From the 33 species, about 22 species belonged to wetland birds and 11 species belonged to the terrestrial habitat. Among the birds spotted, 25 species were residents (76%), 5 species were locally migrant (15%) and 3 species were migrants (9%). The species abundance was highest during March and lowest in June. During the study, species such as carnivorous, omnivorous, insectivorous, frugivorous and mixed guild were reported. Two of the recorded species such as Oriental Darter (Anhinga melanogaster) and Black-headed Ibis (Threskiornis melanocephalos) came under near threatened (NT) category of the IUCN list. The present study indicates the need for the conservation of Ashtamudi wetland and its bird species.