The objective of the present study was to investigate the immunomodulatory activity of Terminalia belerica on cellular and humoral immunity. Oral administration of the ethanolic extract of bark of Terminalia belerica, at the doses of 100mg/kg in mice, dose-dependently potentiated the delayed-type hypersensitivity reaction induced by sheep red blood cells (SRBC) . It significantly enhanced the production of circulating antibody titre in mice in response to SRBC.