Objective To explore the effect of Xchromosomelinked inhibitor of apoptosis (XIAP) antisense oligonucleotides (ASODN) on cell growth, apoptosis and chemosensitivity of laryngeal carcinoma Hep2 cells by transfecting XIAP ASODN into Hep2 cells. Methods Transfection of XIAP ASODN into Hep2 cells was carried out by lipofectamine assay. Transfection efficiency was observed by inversephase fluorescence microscope. Cell growth inhibition rate was detected with MTT assay. The level of XIAP mRNA was measured with RTPCR. Cell apoptosis rate as well as the expression of XIAP protein was detected with flow cytometry. Results Transfection efficiency of XIAP ASODN of different concentrations was more than 90% and the differences between groups of different dose of XIAP ASODN were statistically insignificant. DDP of all concentrations could inhibit cell proliferation with dose and time dependent manners, and the differences were statistically significant (P<0.05). The apoptosis rate increased gradually with the raise of DDP concentration (P<0.05). The cell inhibition rates of all concentrations of XIAP ASODN groups with 3 ug/ml DDP at different stages of time were higher than those of the ASODN group and DDP group, and the differences were statistically significant (P<0.05). The flow cytometry results showed that the apoptosis rate in DDP combined with ASODN group was significantly higher than that of the DDP group (P<0.01). The relative expression levels of XIAP mRNA of DDP combined with ASODN group and ASODN group were downregulated. The flow cytometry results showed that the fluorescence index (FI) in ASODN group was lower than those of the blank group, lipofectamine group and SCODN group (P<0.05), According to the Pearson’s correlation analysis, there was positive correlation between the cell apoptosis rate and the fluorescence index (FI) (r=-0.976,P<0.01). Conclusion Transfection of XIAP ASODN into Hep2 cells can inhibit cell proliferation, induce apoptosis and enhance the sensitivity of laryngeal carcinoma Hep2 cells to chemotherapy.