Objective : The genus Glycyrrhiza has been used in food and traditional herbal medicine. Glycyrrhiza new varieties Wongam and Sinwongam have been developed by Korea Rural Development Administration and investigated to register on Korean Pharmacopoeia of the Ministry of Food and Drug Safety. The aim of this study is to investigate the immunomodulatory effect of Wongam and Sinwongam comparing with listed Glycyrrhiza species (Glycyrrhiza uralensis Fischer and G. glabra Linne) for evaluations about pharmacological effect of Glycyrrhiza new varieties. Methods : We studied the immunomodulatory effect of Wongam and Sinwongam compared with G. uralensis and G. glabra using THP-1 cell in vitro model. The cells were treated with phorbol 12-myristate 13-acetate (PMA) for differentiation and stimulated with lipopolysaccharides (LPS) to induce immune activation. We analyzed and compared the effects Glycyrrhiza new varieties and listed Glycyrrhiza species using nitric oxide (NO) assay, western blot, and reverse transcription-quantitative polymerase chain reaction analysis. Results : Wongam and Sinwongam showed no cytotoxicity in THP-1 cells. Wongam and Sinwongam, and listed Glycyrrhiza species increased NO production, and cyclooxygenase (COX)-2 expression with or without LPS in differentiated THP-1 macrophages. Furthermore, Wongam and Sinwongam and listed Glycyrrhiza species upregulated the mRNA expressions of T helper type 1 (Th 1)-associated cytokines in LPS-stimulated THP-1 macrophages. Conclusion : These results indicated that Wongam and Sinwongam would have effect of enhancing immune response through the increase of NO and COX-2 expression, and activate Th1-associated cytokines. The findings of this study suggest the wide applicability of Glycyrrhiza new varieties.