The present study investigated the effect of salicylic acid (SA) and sodium nitroprusside (SNP) on germination and activity of antioxidant enzymes in soybean under oxidative stress using a factorial experiment based on completely randomized design with three replications. Treatments included SA (0 and 1 mM), SNP (0, 30, and 60 µM), and H2O2 (0, 50, and 100 µM). Results showed that the highest germination percentage (97%) was related to 1 mM SA without SNP and H2O2 which was 6% greater than the control and the highest germination rate (0.72) was related to 1 mM SA and 60 µM SNP without H2O2 (6.63% greater than the control). The highest activity for superoxide dismutase (89.17 units mg -1 protein) was achieved by application of 100 µM H2O2 without SNP. In conclusion, oxidative stress increased all antioxidant enzymes while SNP application decreased the enzyme activity and stress severity. Manuscript profile