Abstract: A nasal cannula and mouthpiece assembly for delivering oxygen to a person is provided having a nasal cannula, at least two mouthpieces, two pairs of oxygen supply tubes and two sets of adjustors. Each mouthpiece has a first outer end for receiving oxygen and a second outer end with a first and second opening. The first opening delivers oxygen across lips of a mouth of the person and the second opening delivers oxygen inside the mouth from the sides. A sleeve member encloses each of the mouthpieces and positions the mouthpieces in front of the sides of the mouth. The oxygen supply tubes of the first pair deliver oxygen to the nasal cannula and those of the second pair deliver oxygen to the first pair and to the mouthpieces. The two sets of adjustors adjust the lengths of the oxygen supply tubes of the first pair and the mouthpieces to provide a desired fit of the assembly on the person.