Based upon preliminary study showing stimulation of glucose uptake by 20(R)-$Rg_3$, a stereoisomer of 20(S)-$Rg_3$ ginsenoside found in red ginseng, we investigated the action mechanism of 20(R)-$Rg_3$ in differentiated C2C12 myotubes. It was found that 20(R)-$Rg_3$ stimulated translocation of glucose transporter 4 (GLUT4) and glucose uptake in a concentration-dependent manner. In addition, 20(R)-$Rg_3$ phosphorylated AMP-activated protein kinase (AMPK) and $Ca^{2+}$/Calmodulin-dependent protein kinase kinase (CaMKK) in time- and concentration-dependent manners. In the meantime, 20(R)-$Rg_3$-induced glucose uptake and translocation of GLUT4 were attenuated in the presence of compound C (an AMPK inhibitor) or STO-609 (a CaMKK inhibitor). Taken together, this study is the first to demonstrate that 20(R)-$Rg_3$ stimulated the glucose uptake via translocation of GLUT4 and this effect was seemed to be mediated by CaMKK-AMPK pathways in C2C12 myotubes.