Cell migration is a key physiological ability in wound healing, organ regeneration and cancer metastasis1,2. This ability in cancer cells enables them to invade the normal tissues in their vicinity. A few studies have revealed the suppressed cancer cell migration in the presence of gold nano-particles (AuNPs)3–6. In addition, alteration on cytoskeleton properties by x-irradiation has been reported7 . However, the close investigation for the effects of AuNPs on cancer cell migration have not been previously performed and the effects of AuNPs combined with X-ray irradiation also remained unclear. In this in vitro study, we investigated the effects of AuNPs on the cell migration for two types of cancer cells to determine the cellular response to the AuNPs. Furthermore, we investigated the combined effects of AuNPs and X-ray on cell migration.