The objective of this paper was determining population and species diversity of water birds and waders in Gandoman wetland during one year from mid-September 2017 to mid-September 2018 using SDR-IV software. Result showed from 70 identified birds, 28 species were waterfowl and 42 species were waders. The largest population was belong to Fulica atra. Anatidae with 33.19 percent frequency was the largest family and Burhinidae with 0.003 percent was the smallest family. Winter had largest bird counting (14413 birds) and summer had the lowest bird counting (4039). Results obtained using biodiversity index showed that spring had the biggest diversity in terms of Shanon-Winer (2.97), Simpson (10.71) and Margalf (6.69) diversity and biggest evenness (0.92) in terms of Smith & Wilson. The largest species richness was found in spring (60 species) and the lowest one was found in summer (40 species). The largest bird frequency (bird number) was belong to waterfowl (81.57 %) and the lowest frequency was belong to waders (18.43). In contrast, the largest number of species (60 percent) was belong to waders and the lowest one was belong to waterfowl (40 percent). The results showed that Gandoman wetland had the highest numerical values of richness and evenness of water birds and waders in spring, and this indicated the quality and desirability of the wetland in spring compared to other seasons.