It was found that microwave irradiation under strictly controlled temperature conditions drastically enhanced the catalytic atropo-enantioselective Corey-Bakshi-Shibata (CBS) reduction of biaryl lactones. Since the high enantioselectivity was maintained completely compared with conventional heating conditions, the present enhancement is not caused by simple microwave heating. It was also revealed that the microwave irradiation could accelerate the racemization of the atropo-enantiomers of optically active biaryl lactone. It could be concluded that the drastic enhancement with retention of the high enantioselectivity was caused not by simple heating, but by some direct microwave effect on the substrate molecule.