Emodin is a bioactive compound isolated from the root and rhizomes of Rheum plamatum L. (polygenaceae), which is known as a traditional Chinese and Japanese medicine. In the present study, the effect of emodin on YD-15 mucoepidermoid carcinoma cells and its molecular mechanism were investigated. This study shows that emodin significantly inhibits the growth of YD-15 cells. Activation of caspase-3 and PARP is triggered by emodin and it increases sub-G1 population and the number of YD-15 cells with nuclear condensation and fragmentation. In addition, we found that emodin significantly decreases myeloid cell leukemia 1(MCL-1). These results suggest that MCl-1 is an important molecule for emodin-induced apoptosis. Taken together, emodin inhibits cell viability and induces apoptosis via down-regulation of MCL-1 and it can be a new potent anticancer drug candidate for the treatment of mucoepidermoid carcinoma