The main objective of this study was to determine the effect of microwave thawing at different power levels on the physicochemical properties of chicken breast. Each frozen chicken breast samples were thawed in microwave oven at microwave power levels of 125, 250, and 375W. To compare the effect of microwave thawing on meat quality, refrigerator thawing was used as a control. As the microwave power level increased, the thawing rate increased and temperature differences between the edge position and center position of the samples also increased. Treatment at a power level of 250 W resulted in a lower thawing loss and a higher moisture content, water holding capacity, and tenderness than the other treatments (p<0.05). However, there were no significantly differences of proximate composition excluding moisture content, pH, lightness, and yellowness. The use of excessive input energy during microwave thawing (higher microwave power level) damaged the physicochemical properties of the thawed chicken breast; therefore, the microwave power level of 250 W is the best thawing method on the frozen chicken breast to minimize the changes in meat quality in this study.