A respiratory face mask is provided suitably sized and configured to engage the nose portion, mouth portion and chin portion of a patient's face. The face mask is characterized by a cup-like shell or receptacle member defining a peripheral flange and a flexible inflatable hollow sealing cushion on the shell member flange. Headstrap fastener projections extending upright on the flange are adapted to accommodate an elastic headstrap that adjustably may be removably slidingly coupled to the projections to hold the mask in place on a patient's face and head.