Ginsenoside Rp1 (G-Rp1) is a ginseng saponin derivative with chemopreventive and anti-cancer activities. In this study, we examined the regulatory activity of G-Rp1 on the functional activation of macrophages. G-Rp1 remarkably inhibited TNF-$alpha$ production, LPS-induced cell cytotoxicity, NO production, ROS generation, and phagocytic uptake from lipopolysacchride (LPS)-activated RAW264.7 cells. According to structural feature study using several G-Rp1 analogs, two carbohydrates (glucose-glucose) at R1 position were observedto be highly effective, compared to other structural derivatives. Although the inhibitory activities of G-Rp1 on macrophage functions were not remarkable, several points that G-Rp1 was known to be safe, and that this compound was orally effective, suggest that G-Rp1 may be beneficial in treating macrophage-mediated immunological diseases.