The aim of the current research was to evaluate the immunomodulatory potential of methanol extract of Aegle marmelos in an experimental animal model of cellular and humoral immunity. Administration of methanol extract of Aegle marmelos (500 and 1000 mg/kg, p.o.) and Ocimum sanctum (100 mg/kg, p.o.), produced significant increase in adhesion of neutrophils and an increase in phagocytic index in carbon clearance assay. Both doses of Aegle marmelos prevented the mortality induced by bovine Pasteurella multocida in mice. Moreover, all treated groups demonstrated significant elevation in circulating antibody titre in the indirect haemagglunation test. From the above results, it can be concluded that methanol extract of Aegle marmelos possess immunomodulatory potential by stimulating cellular and humoral immune mechanisms. However, low dose of methanol extract of Aegle marmelos was more effective for augmenting cellular immunity, whereas, high dose was more inclined towards humoral immunity.