Resveratrol, a dietary polyphenol found in grapes, has been proposed to act as a chemopreventive or anti-tumor agent in numerous epidemiologic studies. In this study, we investigate the antitumor and immunomodulation effects of resveratrol on mouse lymphocytic leukemia cells L1210 both in vitro and in vivo. Our finding indicates that resveratrol inhibits proliferation, induces apoptosis, and influences cell cycle of L1210 cells in a dose- and time-dependent manner in vitro. Furthermore, resveratrol can exert a dose-related regulatory effect on both innate and specific immune function to L1210-bearing mice. A normalization of CD4/CD8 ratios is noted as well as an enhancement of lymphocyte proliferation, NK cell activity and anti-SRBC titers. Interleukin-6 cellular content and release are suppressed by resveratrol as well as mRNA expression. In conclusion, the data provide new findings with respect to resveratrol mechanism of action to mouse lymphocytic leukemia.