Aurora-A, a serine/threonine kinase that is overexpressed in certain human cancer cell lines, plays an important role in mitotic progression. Aurora-A has also been reported to be involved in the activation of nuclear factor kappa B (NF-κ;B). The purpose of the present study was to identify the role of Aurora-A in the radiation-induced activation pathway of NF-κ;B. Wild-type and Aurora-A knockdown (Aurora-A^KD) HeLa cells were irradiated with 4 Gy of γ rays and the EMSA, luciferase reporter gene assay and immunoblot analysis were performed. The siRNA-based gene knockdown and overexpression system was adopted to elucidate the role of Aurora-A in radiation-induced NF-κ;B pathway activation. The clonogenic survival study indicated that Aurora-A^KD cells and the wild-type cells transfected with Aurora-A siRNA or RelA/p65 siRNA were more radiosensitive than the wild-type cells. In both the wild-type and Aurora-A^KD cells, radiation caused Iκ;B kinase-mediated phosphorylation, degradation of Iκ;Bα and phosphorylation of RelA/p65. The nuclear translocation of RelA/p65 was also similar in the wild-type and Aurora-A^KD cells. However, RelA/p65-DNA binding was markedly suppressed in Aurora-A^KD cells compared to that in wild-type cells. It was concluded that Aurora-A enhances the binding of NF-κ;B to DNA, thereby increasing the gene transcription by NF-κ;B and decreasing the radiosensitivity of the cells.