Aim To investigate the effects of Genistein on endothelial nitric oxide synthase (eNOS) and nuclear factor-κB (NF-κB) expression in endothelial cells. Methods Human umbilical vein endothelial cells (HUVEC),which were incubated with ox-LDL(100 mg/L),were treated with different concentrations of Genistein(10,50 and 100 nmol/L) for 24 hours. Cell activities were detected by MTT method,the mRNA expression of eNOS was detected by real-time RT-PCR,the protein expression of eNOS and NF-κB was determined by Western blotting. Results Compared with control,ox-LDL decreased cell activities,down-regulated the expression of eNOS mRNA and protein,and up-regulated the expression of NF-κB protein (P><0.05). However,Genistein increased cell activities,up-regulated the expression of eNOS mRNA and protein,and down-regulated the expression of NF-κB protein (P><0.05). Furthermore,these effects were dose-dependent (P><0.05 ). Conclusion Genistein could upregulate the expression of eNOS,and downregulate the expression of NF-κB in HUVEC.