A 60-d feeding trial was conducted to evaluate the effects of Saccharomyces cerevisiae and β-glucan on the growth performance, feed utilization and immunity response of Macrobrachium rosenbergii. Prawns (0.19 ± 0.01 g) were fed with the basal diet (group C) or other three experimental diets supplemented with S. cerevisiae (group S), β-glucan (group G) or their combination (group GS), respectively. Results showed that the growth performance of prawns was significantly promoted in group S and GS (p < 0.05). Immunostimulants supplementation significantly increased the protease activity and the highest amylase activity was found in group G (p < 0.05). The highest phagocytic index of prawns was observed in group GS (p < 0.05), and the respiratory burst activity was significantly improved in group S and GS (p < 0.05). Furthermore, immunostimulant supplementation significantly increased the gene expression of the antioxidant and antimicrobial enzymes of prawns (p < 0.05). Immunostimulant supplementation also significantly increased the gene expression of prophenoloxidase, tolllike receptors, heat shock protein 70 and lectins(p < 0.05). Conclusively, S. cerevisiae and β-glucan both could be used as potential immunostimulants in prawns farming.Considering the comprehensive effects, their combination was more effective in promoting the growth and immunity of prawns.