Diallyl sulfide (DAS) is a component of garlic (Alliaceae family). Although diallyl polysulfide has been shown to exhibit anticancer activities, no report explored DAS-affected cell death in human cervical cancer cells in vitro. This study investigated DAS affected on cell-cycle regulation and apoptosis in human cervical cancer Ca Ski cells. DAS at 25-100 μM decreased the viability of Ca Ski cells by increasing G0/G1 phase arrest followed by induction of apoptosis in concentration- and time-dependent effects. Flow cytomteric assay indicated that DAS (75 μM) promoted the production of Ca(2+) accumulation and decreased the level of mitochondrial membrane potential in Ca Ski cells. Western blotting showed that 75 μM of DAS-induced G0/G1 phase arrest was mediated through the increased expression of p21, p27, and p53 with a simultaneous decrease in CDK2, CDK6, and CHK2 expression. The characteristics of apoptosis, such as morphological changes and DNA condensation, altered the ratio of Bax/Bcl-2 and sub-G1 phase occurred in Ca Ski cells after exposure to DAS. Furthermore, DAS induced mitochondrial dysfunction, leading to the release of cytochrome c for causing apoptosis in Ca Ski cells. These findings suggest that DAS might be a potential chemotherapeutic agent for the treatment of cervical cancer.