Different immunostimulants were investigated to detect changes in the activity of non-specific immune response and disease resistance of striped catfish (Pangasianodon hypophthalmus). In current experiment, striped catfish were injected with five immunostimulants such as beta-glucan (10mg/kg fish), bovine lactoferrin (500mg/kg fish), chitosan (6mg/kg fish), levamisole (5mg/kg fish) and vitamin C (1,000 mg/kgfish). The plasma cortisol and glucose were measured as stress biomarkers, the respiratory burst activity, lysozyme, complement activity and total of immunoglobulin were analysed as indicator for humoral immune response. The challenge test were conducted with bacteria Edwardsiella ictaluri in day 17th and 21st after immunostimulant injection in order to find out the effects of the immunostimulants on fish immune system and their protection from bacteria. The obtained results indicated that the plasma cortisol and glucose were rather low and did not differ significantly among treatments (p>0.05). In contrast, the respiratory burst and lysozyme activity were significantly increased in immunostimulants treatments (p<0.05) if compared to those of the control treatment and displayed the highest value in levamisole treatment. In addition, the complement activity and total immunoglobulin were also enhanced in fish injected with beta-glucan, bovine lactoferrin, chitosan and levamisole, but fish injected with vitamine C did not showed any significant difference if compared to those of the control treatment. After challenge test, accumulated mortality was reduced in immunostimulant treatments in both day 17th and day 21st if compared to that of the control treatment. It may suggest that beta-glucan, bovine lactoferrin, chitosan and levamisole could enhance non-specific immune response in striped catfish and protect fish against bacteria.