Rapid and accurate identification of the gender of monomorphic birds, which are difficult to determine by direct observation, is of great significance in the study of avian ecology. Discriminant analysis according to morphological characteristicshas has been frequently used for sexing individuals in monomorphic species because of its fast, simple procedure and high accuracy. This study used discriminant analysis to identify the gender of five monomorphic sandpiper species at Chongming Dongtan, a stopover site of the East Asian-Australasian Flyway (EAAF): Great Knots Calidris tenuirostris, Red Knots C. canutus, Red-necked Stints C. ruficollis, Sharp-tailed Sandpipers C. acuminate, and Terek Sandpipers Xenuscinereus. Five morphological characteristics (body weight, wing length, bill length, head and bill length, and tarsus length) were measured during spring migration in 2008. Firstly, we identified the gender of the individuals in the five species using molecular biological method. Then we used independent t tests to compare the difference in the morphological characteristics between the males and females. The degree of overlap in morphological characteristics between males and females as well as the sexual dimorphism index were calculated for each species. Finally, we used discriminant analysis to deduce the gender of each individual according to morphological measurements and compared the results with that from molecular biology method. The morphological characteristics of the males were significantly larger than that of the females in Sharp-tailed Sandpipers, while the females were larger than the males in other four species (Table 1). The sexual size dimorphism index of morphological characteristics in the five sandpiper species varied in 0.5%﹣25.3% (Table 2), and the interspecific overlaps of morphological characteristics varied in 29.4%﹣98.6% (Table 1). The accuracy of gender identification using discriminant analysis was 0.69 ± 0.06﹣0.96 ± 0.01, with the highest in the Sharp-tailed Sandpipers (96%) while the lowest in the Terek Sandpipers (69%, Table 3). The difference in morphological characteristics between the genders affected the accuracy of gender discrimination. In addition, sex ratio might also affect the accuracy of gender discrimination. The sex ratio estimated using discriminant analysis is similar to that using molecular biological method (Table 3), indicating that the discriminant analysis has a high reliability in determining the sex ratio of population.