A nasal positive airway pressure device is provided having a pair of nasal members each having a cannula tip to be inserted into the nares of the patient. Each cannula is tapered from a substantially circular cross-section outside the patient's nostril to a substantially oval cross-section at the tip inserted into the nostril. An inflatable cuff surrounds each cannula with the interior space of the cuff communicating with the lumen of the cannula through at least one aperture in the side wall of the cannula. The nasal members are connected to one or more flexible hoses which, in turn, are connected to a source of positive air pressure. In use, positive air pressure is supplied to the each cannula tip through the air hoses and nasal members. The positive air pressure inflates the cuffs to hold the nasal members in place and to effect treatment, The tapered tip configuration, soft inflatable cuffs and adjustable positioning of the nasal members and tip provide a device which is more comfortable to the user. A variable diameter orifice for nasal positive airway pressure treatment is also contemplated.