A breathing mask includes an elastomeric cushion with a sealing lip having an outer engagement surface configured to sealingly abut against the patient's face. The sealing lip has a plurality of zones. A first zone has an elastomeric wall and includes a portion of the elastomeric cushion adapted to abut against a bridge of a patient's nose. A second zone has an elastomeric wall and includes a portion of the elastomeric cushion adapted to abut against the patient's face at a location opposite the first zone. A pair of intermediate zones include portions of the elastomeric cushion adapted to abut against the patient's face between the first and second zones and have relatively thick elastomeric walls compared to the elastic walls of the first and second zones so that the pair of intermediate zones has a higher load-bearing capability than the first and second zones.