We evaluated the immunomodulatory effects of proanthocyanidin-rich extract (PAE) from Pinus radiata bark in broiler. Proliferation of peripheral blood mononuclear cells and thymocytes was significantly enhanced in 2.5, 5, 10 mg/kg PAE-treated broiler chickens. Proliferation of splenocytes was significantly enhanced in 1.25, 2.5, 5, 10 mg/kg PAE-treated broiler chickens. These effects were markedly enhanced by the presence of LPS, which acts on B cells responsible for humoral immunity, and Con A, which acts directly on T cells involved in cell mediated immunity. PAE significantly promoted the expression of interleukin-18 and interleukin-$1eta$. Thus, PAE from P. radiata possesses immunomodulatory effects in broiler chickens.