Abstract: A twin-bottle nursing bottle includes an outer bottle having a mouth at the top; an outer cap fastened to the mouth of the outer bottle through a screw joint to hold a nipple; an inner bottle disposed inside the outer bottle; a cup-like inner cap supported above the mouth of the outer bottle to hold the inner bottle inside the outer bottle; and a diversion control switch received within the outer cap between the nipple and the cup-like inner cap and turned to let a first fluid in the outer bottle or a second fluid in the inner bottle flow into the nipple for suction by the baby or to let both the first and second fluids flow into the nipple simultaneously.