Objective: To investigate the influence of brain-derived neurotrophic factor (BDNF) on the chemosensitivity of human hepatocellular carcinoma Bel-7402 cells to fluorouracil (5-FU). Methods: Bel-7402 cells were treated with 5-FU alone (5-FU group) or 5-FU plus BDNF (5-FU+BDNF group) respectively, and the Bel-7402 cells without treatment served as control group. The cell growth and apoptosis were determined by MTT assay, colony formation assay, and flow cytometry respectively, and the bcl-2 mRNA expression in the cells was measured by RT-PCR method. Results: The OD value and number of colonies were significantly decreased, apoptosis rate was significantly increased, and bcl-2 mRNA expression was markedly down-regulated in the cells of 5-FU group, and all the differences had statistical significance compared with those of control group (all P<0.05); the changes in all of the above variables in cells of 5-FU+BDNF group were not evident, and the differences showed no statistical significance compared with those of control group (all P>0.05). Conclusion: BDNF can reduce the chemosensitivity of hepatocellular carcinoma Bel-7402 cells to 5-FU, and this effect may be associated with BDNF up-regulating the bcl-2 expression and thereby inhibiting cell apoptosis.