This study was conducted to assess the performance of broiler chickens based on some hematological and immunological profile, upon inclusion of aqueous extract of Withania somnifera (W. somnifera) in their drinking water. For this purpose, 240 a-day-old broiler chicks were purchased from a local hatchery and divided into four groups i.e. WST-0, WST-I, WST-II and WST-III. Group WST-0 was kept as control, while chicks in group WST-I, WST-II and WST-III were offered in their drinking water with an extract of W. somnifera at 10, 20 and 30g/L for 35 days, starting from day 1 of age. Feed intake and body weight were recorded on regular basis and hematological and immunological profile of the birds was analyzed at the end of experiment. Administration of W. somnifera extract resulted in significantly higher feed intake and body weight of birds in all treated groups. An increase in the values of Hb, PCV and TLC was noted in the treatment groups. A non significant difference was noted in the counts of neutrophils, lymphocytes, eosinophils and monocytes in all treatment groups as compared to control. Antibodies titers against IB and IBD were significantly higher in all treatment groups as compare to the values shown by the chicks in control group. Findings of this study indicated that administration of W. somnifera extract to broiler chicks improve their feed intake, body weight gain, hematological profile and immunological status.