The breathing mask with nasal cannula includes a breathing mask having a frontal air inlet port that communicates with an air inlet in a removable mask retainer. The air inlet of the mask retainer is adapted to receive ambient air provided by a non-invasive ventilation (NIV) device. In addition, the mask includes an oxygen pass-through connector tube that is sealed in place in the front of the mask. A nasal cannula is connected to the interior portion of the connector tube and adhesively secured to the patients nose. The mask and retainer are then secured over the patients nose and mouth, and an oxygen supply tube is connected to the external end of the pass-through tube of the mask. Airflow is adjusted from the NIV and to oxygen flow is adjusted to the cannula to provide the patient with the required air and oxygen flow for proper blood saturation.