This study was performed to examine the quality and antioxidant activity of muffin containing black garlic extract powder that was stored for 9 days at room temperature. Black garlic extract powder was added to the muffin batter at concentrations of 0, 1, 4, 8, and 12%. Specific gravities of muffin batters increased as black garlic extract powder increased, whereas, height and specific volume of the muffins decreased. For the color of muffin crust and crumb, lightness decreased as the level of garlic extract powder increased, whereas redness and yellowness increased. For sensory evaluation, the color, flavor, softness, and chewiness of the muffins containing 1% black garlic extract powder were superior compared to those of other samples. Scores for taste and overall acceptability were the highest in muffin containing 4% black garlic extract powder. The antioxidant activity of muffins measured by DPPH(2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay increased as the level of black garlic extract powder increased. Further, the TBARS(thiobarbutric acid reactive substance) content of the muffins containing various levels of black garlic extract powder was lower than that of control.