We studied the effects of ginsenoside-$Rg_1$ (G-$Rg_1$) extracted from Panax ginseng C.A. Meyer on $p56^{kk}$ kinase and cell proliferation in Jurkat T cells. $p56^{kk}$ was maximally activated within 5 min after the treatment of 16.7 $mu extrm{g}$/ml of G-$Rg_1$ increasing the activity by 1.2-2 times relative to untreated control, thereafter its activity was gradually decreased to the level of untreated control. The action of EGTA on the kinase was altered by the addition of G-$Rg_1$, accompanying the band shift of $p56^{kk}$ to $p60^{kk}$. In addition, G-$Rg_1$promoted cell proliferation in a concentration-dependent manner. These results suggest that G-$Rg_1$ may be involved in T cell receptor-CD3 (TCR) signaling via the activation of $p56^{kk}$ and the chance of cellular calcium concentration.