The anticancer effects of leek (buchu in Korean) kimchi were evaluated in the human cancer cells: AGS gastric adenocarcinoma cells, HT-29 human colon adenocarcinoma cells and HL-60 leukemia cells. The leek kimchi (fermented for 6 days at 15$^{circ}C$) was fractionated into 7 groups: methanol extract, hexane extract, methanol soluble extract MSE), dichloromethane (DCM) fraction (fr.), ethyl acetate fr., butanol fr. and aqueous fr. Most of the leek kimchi tractions inhibited the growth of AGS and HT-29 cancer cells in a dose dependent manner. In particular, the DCM fr. showed the highest inhibitory effect among the tractions. Treatment with the DCM fr. (0.1 mg/mL) reduced the survival rates of AGS and HT-29 cancer cells to 19% and 37% of the controls, respectively. Moreover the DCM fr. of the leek kimchi arrested G2/M phase in the cell cycle and induced apoptosis in HL-60 human promyelocytic leukemia cells. These results indicate that the leek kimchi exerted an anticancer effect on those human cancer cells, and that the DCM fr. arrested G2/M phase in the cell cycle and induced apoptosis in the leukemia cells.