Eugenol is commonly used in dentistry for the sedation of toothache, pulpitis, and dental hyperalgesia. This study was performed to investigate the apoptotic effect of eugenol to human osteosarcoma (HOS) cells and the potential use of this compound in osteosarcoma cells. Eugenol showed the apoptotic effect in HOS cells in dose- and time-dependent manner. Fragmentation and condensation of DNA were showed by TUNEL assay, Hemacolor stain and Hoechst stain. In the DNA electrophoresis analysis, cells showed DNA degradation characteristic of apoptosis with a ladder pattern of DNA fragments. Apoptosis-related factors were analyzed by western blotting. Cells treated with eugenol showed caspase-3, PARP, lamin A and DFF-45 cleavage. Eugenol treatment induced caspase-3 cleavage and activation. Cleavages of PARP, DFF-45 and lamin A were accompanied with activation of caspase triggered by eugenol in HOS cells. Though this study needs more investigations, these results suggest that eugenol induce apoptosis via caspase dependent pathway in HOS cells and eugenol may constitute a potential antitumor compound against osteosarcoma cells.