Levamisole hydrochloride (Lev.HCl) has been acclaimed to boost immune response particularly in immunocompromised state. Its routine use as an immunomodulator in poultry production is yet to be well embraced, thus its effects of on cellular immunity and flock performance of commercial broilers were evaluated. One hundred and fifty Anak broiler chicks were separated into two groups of 75 each. Broilers in group 1 were sensitized with 150µg of Staphylococcus aureus antigen each at 4 and 5 weeks, while those in group 2 were not sensitized. Each group was further divided into subgroups A, B, and C. Levamisole hydrochloride (40 mg/kg) was administered orally to 1A and 2A at 45 and 46 days of age and to 1B and 2B at 47 and 48 days of age, while 1C and 2C were not treated. At 47 days of age, 12 broilers from all subgroups were challenged with 75µg of S. aureus antigen each at the right wattle. Wattle thickness was measured till 72 hours post challenge (pc) and delayed wattle reaction (DWR) was determined. Tissues were harvested at 72 hours pc for histopathology. Morbidity, mortality and live weights at 8 weeks of age were recorded. DWR peaked at 4 hours pc in 1A (2.22 ± 0.21 mm) and 1B (2.96 ± 0.21 mm) and 24 hours pc in 1C (3.39 ± 0.34 mm), the difference being significant (p<0.05). Inflammatory lesions were observed in wattles of sensitized subgroups and were more severe in 1C. Mortality rates were 4.17% and 29.17% in 1A and 1C respectively. Mean live weights in A and B i.e. 1.57± 0.06 kg and 1.56 ± 0.06 kg respectively, were significantly higher (p<0.0) than 1.43 ± 0.08 kg in C. Levamisole enhanced DTH via an early response, improved broiler liveability, and its anti-inflammatory property was confirmed.