Updated project metadata. Because of the tremendous use of NPs in the agricultural sector (Vernikov et al., 2009) and their interactions with the plants, the effect of NPs in plants needs to be explored at the molecular level. To investigate the effects of varying sizes of silver NPs on early-stage soybean under flooding stress, morphological and proteomic analyses were performed. In this study, 5 ppm silver NPs were used because 5 ppm of silver NPs were reported to promote the soybean growth under flooding stress (Mustafa et al., 2015). In the present study, the silver NPs induced changes, in the soybean proteins under flooding stress, was evaluated using gel-free proteomic technique.