Abstract: Objective: To investigate the expression of the Omi/HtrA2 and its significance in carcinogenesis and development of the laryngeal squamous cell carcinoma (LSCC). Methods: The expressions of Omi/HtrA2 mRNA and protein were determined using immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction in 20 cases with LSCC and 8 with polyp of vocal cords (VCP). Results: No immunoreactivity of Omi/HtrA2 was observed in the paraneoplastic tissues, but there was an evident Omi/HtrA2 immunoreactivity in LSCC and VCP tissues, which showed no significant difference between them (P>0.05). The expression of Omi/HtrA2 mRNA in well differentiated LSCC cases was significantly higher than that in poor differentiated type, VCP and normal tissues (P<0.01). Conclusion: Omi/HtrA2, as an important apoptotic promoter, appears to be closely related with the genesis and development of LSCC. A better understanding of its functions may help to develop the newstrategies for treatment of the cancer.