Curcuma zedoaria has been used as a traditional agent against malignant diseases. To elucidate detailed mechanisms producing such an activity, characterization and determination of molecular mechanisms of its antitumor effects was conducted. Inhibiting activities against cell proliferation, invasion and colony formation, and expression levels of corresponding molecules were investigated using human esophageal cancer TE-8 cells treated with the rhizome extract from C. zedoaria. Antitumor effect of the extract administered orally was also examined in tumor-bearing mice. The extract possessed strong anti-proliferation and invasion activities against TE-8 cells. Further, upregulated PTEN and downregulated phosphorylated Akt, mTOR and STAT3 expressions in the cells were induced shortly after treatment with the extract, followed by attenuation of FGFR1 and MMP-2, activation of caspase-9, caspase-3 and PARP, and suppression of Bcl-2 expressions, which led the cells to apoptotic cell death. Furthermore, tumor formation in mice was significantly suppressed through the oral administration of the extract. Taken together, these results suggest that the C. zedoaria extract could be a promising agent against esophageal cancer.