Myricetin is a major flavonoid found in various foods that has antioxidant, anti-inflammatory, and anticancer effects. Although the functional effects of myricetin in various cell types are well characterized, it is not known whether myricetin has an effect on stem cell differentiation. In this study, we demonstrate that myricetin inhibits adipogenesis in human adipose tissue-derived mesenchymal stem cells, as indicated by decreased accumulation of intracellular lipid droplets. The mRNA levels of CCAAT-enhancer-binding proteins (C/EBP)-${alpha}$, peroxisome proliferator-activated receptor-${gamma}$ (PPAR-${gamma}$), lipoprotein lipase, fatty acid binding protein (aP2), and adiponectin decreased significantly following treatment with 30 ${mu}M$ myricetin. C/EBP-${alpha}$ expression was inhibited from the beginning of differentiation in response to the myricetin treatment. PPAR-${alpha}$ was significantly inhibited beginning at day 9. These results suggest a novel effect of myricetin on adipocyte differentiation in human adipose tissue-derived mesenchymal stem cells and the possibility that myricetin might affect the differentiation of other types of stem cells.