Red wine polyphenol, trans-resveratrol (trans-3,4',5-trihydroxy stilbene), has potent chemopreventive effects against various tumors. In this study, we found for the first time that resveratrol rapidly induces S phase cell cycle arrest of human malignant B cells including myeloma cells in dose- and time-dependent manners, followed by S phase cell cycle arrest through ATM/Chk pathway. Resveratrol-induced apoptosis occurs in association with the activation of caspase-3 and the loss of mitochondrial transmembrane potentials. In addition, resveratrol induces the phosphorylation of p38 MAP kinase, and specific inhibition of p38 MAP kinase abolishes the resveratrol-induced apoptosis, indicating that activation of the p38 MAP kinase pathway is required for inducing apoptosis in malignant B cells. These results suggest that resveratrol may have potential as a novel therapeutic agent for the patients with B cell malignancies including multiple myeloma.