The work is to investigate the role of the P44/42 mitogen-activated protein kinases in proliferation disorder of epiglottis carcinoma induced by X-ray irradiation. After obtaining the tissues from the radiation−induced epiglottis carcinoma, we observed the P44/42MAPK protein expression level and the phosphoryation level in epiglottis carcinoma by western blotting, and the mRNA level by semi-quantitative RT−PCR. The results showed that The P44/42MAPK expression of protein and mRNA was significantly higher in lepiglottis carcinoma than in normal tissue nearby the tumor. And the level of P44/42MAPK phosphoryation in epiglottis carcinoma was higher than in that of the normal tissue. The results suggest that P44/42MAPK may play a role in proliferation disorder of epiglottis carcinoma l induced by the radiation.