To study the combinational effects of bcl-2 antisense oligodeoxynucleotide (bcl-2 ASODN) and Rituximab (anti-CD20 monoclonal antibody) on proliferation and apoptosis of B-lymphoma Raji cells in vitro and in vivo, and to explore the possible mechanisms. After bcl-2 ASODN and Rituximab treating on Raji cells respectively or cooperatively, the proliferation of Raji cells, the expression of bcl-2 protein, the apoptosis and the expression of bcl-2 mRNA were detected by MTT assay, flow cytometry (FCM) and RT-PCR, respectively. The combinational antitumor activity of bcl-2 ASODN and Rituximab was evaluated in BALB/c nude mice bearing B-lymphoma inoculated with Raji cells. 5-30 micromol/L bcl-2 ASODN and 1-16 mg/L Rituximab could inhibit Raji cells' growth, induce apoptosis and decrease the expression of bcl-2 protein and bcl-2 mRNA alone. But there was much more effective inhibition of growth and induction of apoptosis by their combination than alone (P<0.01). In tumor bearing mice, combination of bcl-2 ASODN and Rituximab showed a significant inhibitory effect on the growth of transplanted B-lymphoma, resulting in a statistically significant difference compared with alone (P<0.01). It has been found that bcl-2 ASODN combined with Rituximab could significantly inhibit the growth of Raji cells and induce their apoptosis via reinforcing specific down regulation of bcl-2 protein and bcl-2 mRNA expression.