This study was aimed to assess the immunomodulatory effects of Avena sativa (oat) derived arabinoxylans (AXs) in chickens. The extracted AXs were evaluated for immunological and immunotherapeutic activities against coccidiosis in chickens. Oat derived AXs significantly enhanced (P<0.05) the in vitro and in vivo lympho-proliferative responses to T-cell mitogens in chicken. Moreover, significantly higher (P<0.05) humoral immune retorts in terms of antibody titres (GMT) to sheep red blood cells (SRBCs), Newcastle disease and Infectious bursal disease vaccines were also detected in AXs administered chickens; whereas, the difference in organ-body weight ratios was statistically non-significant between AXs administered and control chickens (P>0.05). Results of the challenge experiment revealed that the daily weight gains and percent protection were statistically higher (P<0.05); while, mean oocysts per gram of droppings and lesion scores were lower (P<0.05) in the AXs administered chickens than the control group. In conclusion, oat derived AXs had immunopotentiating potential that persisted against coccidial infection in chickens.