Abstract: Objective To investigate the apoptosis induced by gemcitabine in human NK/T lymphoma cell line SNK-6. Methods MTT, DNA fragmentation and flow cytometry (FCM) analysis were used to detect apoptosis of SNK-6 cells induced by gemcitabine. A human apoptosis microarray containing 88 cDNA fragments was used to detect apoptosis related genes expression difference. Results Gemcitabine could inhibit the growth rate of SNK-6 cells after 48h treatment in a concentration-dependent manner. DNA ladder was observed on DNA electrophoresis and its intensity increased with the increased concentration of gemcitabine. FCM assay revealed that apoptosis cells respectively accounted for 2.1%,8.3%,23.9%,30.9% of total cells respectively after exposure to 2 μg/ml gemcitabine for 4, 8, 24, 48 h. cDNA microarray analysis identified 4 up-regulated and 13 down-regulated genes with more than three-fold change in the first 48h as a consequence of treatment. Conclusion Gemcitabine can induce apoptosis of human NK/T lymphoma cell line SNK-6 cells in a time-dependent and concentration-dependent manner and alter the expression profile of apoptosis-related genes in this cell line, which provides valuable insight into the mechanism of the gemcitabine-induced apoptosis.