We investigated the effect of Takju lees extract on blood glucose levels in the db/db mice (a murine model of type 2 diabetes mellitus). We fed 40 male db/db mice a control diet (G0, AIN93G) and experimental diets containing 1% (G1), 2% (G2), or 4% (G4) Takju lees extract for 4 weeks. We found no difference in food intake and body weight gain among the animal groups. In the G1 and G2 groups, plasma glucose levels decreased significantly between Days 10 and 21 compared with the G0 group. However, we found no difference in plasma glucose levels between groups G4 and G0. The change in insulin concentrations was not significant among these animal groups, and we found no significant difference in glucose transporter 4 (GLUT4) expression in the soleus muscle. These results suggest that the Takju lees extract has a beneficial effect in animals with type 2 diabetes.