Abstract: Objective To investigate the effects of anti-HPV16-ribozyme on the cell proliferation and invasiveness of cultured cervical cancer cell line CaSKi. Methods CaSKi cells were transfected with anti-HPV16 E6-ribozyme and empty eukaryotic expression plasmids via lipofectin and designated as CaSKi-R and CaSKi-P cells respectively. The growth rate, cell colony-forming ability on soft agar, invasiveness and tumorigenicity of CaSKi-R, CaSKi-P, and CaSKi cells were studied using corresponding methods. The expressions of cox-2 and vascular endothelial growth factor (VEGF) mRNA of the 3 cell strains were determined with one-step reverse transcriptional PCR (RT-PCR), and immunocytochemistry was employed for detecting the expressions of COX-2 and VEGF antigens. Results No distinct differences in the growth rate, colony-forming ability on soft agar, cell invasiveness and tumorigenicity were observed between CaSKi and CaSKi-P cells, whereas by comparison, CaSKi-R cells exhibited decreased growth rate, colony-forming ability, the cell invasiveness and tumorgenicity, with also lowered expression levels of cox-2 and VEGF mRNA as shown by RT-PCR analysis. Expressions of COX-2 and VEGF antigens were detected in all the 3 cell strains immunocytochemically, but compared with CaSKi and CaSKi-P cells, the antigen expressions in CaSKi-R cells were significantly weaker. Conclusion Anti-HPV16 E6-ribozyme may partially inhibit the prolifera- tion and reduce the invasiveness of CaSKi cells possibly through decreasing cox-2 and VEGF expressions, which are the important agents for tumor invasion.