Abstract: A baby bottle for bottle feeding of the type wherein a rubber nipple is attached to the mouth of the bottle. An air valve is provided having a seat portion formed integrally with a wall of the bottle and a shutter portion adjustably engageable with said seat portion to operate the valve without interrupting sucking of the nipple by the baby. The nipple has a wall portion spaced away from the baby's mouth, and which wall portion has an outer configuration which varies to provide an indication of the vacuum existing inside the bottle and of tiring of the baby during sucking.