A number of studies have shown that baicalein shows high antitumor activity in vitro and in vivo. In this study, the inhibitory effect of baicalein on human cervical cancer HeLa cells was studied in vitro. HeLa cells were treated with high (100 µg/ml) and low (50 µg/ml) doses of baicalein, and cell growth inhibition rates were examined by the MTT assay. The morphological changes of apoptotic cells were observed under the light and electron microscope, while the rate of cell apoptosis was examined by flow cytometry. The expression of apoptosis-related proteins was analyzed by western blot, and caspase-3 activation was examined by a caspase-3 activity assay and spectrophotometry. The results demonstrated that baicalein inhibits the proliferation of HeLa cells and induces apoptosis in a caspase-3-dependent pathway, through downregulation of the B-cell lymphoma 2 (Bcl-2) protein and upregulation of the Bcl-2-associated X protein (Bax), Fas, Fas ligand (FasL) and caspase-8. Thus, we conclude that baicalein induces apoptosis of HeLa cells via the mitochondrial and the death receptor pathways. Cell apoptosis in HeLa cells was most likely promoted by the activation of the proteolytic enzyme caspase-3 in both pathways.