Immunostimulants get an increasing importance to enhance the immune system and allowing maximum performance in poultry production. The effects of using different immunostimulants on the immune response of broiler chickens to Newcastle disease (ND) and Avian influenza (AI) vaccination were investigated in this study. 100 day-old Ross broiler chicks were randomly divided into 4 groups, 25 birds for each group. Group A was not treated with any immunostimulants and used as a control, while groups B, C and D were supplemented with Imutrix® (oregano oils plus β-glucan), Evit liquid® (Vitamin E plus selenium) and inmunair®17.5 (Propionibacterium acnes and E. coli lipopolysaccharides), respectively. Statistical analysis results demonstrated significant divergence (P < 0.05) in body weight (BW) and feed conversion ratio among the applicable treatments. Birds of group B had the heaviest body weight (2.03 kg), followed by group C (1.87 Kg) and D (1.82 Kg) in comparison to the birds of group A (control, 1.79 Kg). Bursa of Fabricius weight showed non-significant differences among groups except in group B that showed an increase in the Bursa of Fabricius weight more than other groups especially the control group (1.15 g more). Comparable immune response was recorded for both AI and ND vaccination. The highest mean antibody titers were recorded for birds in group B at 14, 28 and 35 days old, while those in group D had the lowest antibody titre values. Thus, supplementing immunostimulants especially Imutrix® and Evit liquid® had a significant positive effect on performance characteristics and immune response against AI and ND vaccination in broiler chickens in contrast to non-treated group, which had low levels of immune response, rapid decreasing and no persistence for keeping high HI titer for long time.