A patient interface gas delivery mask having a forehead and chin support system including a forehead support, a chin support, and a system for supplying a flow of gas to a patient that incorporates such a mask, forehead support, and chin support. The forehead support includes a supporting arm which is adjustably mounted to the mask shell, thereby allowing the adjustment of the distance between the forehead support bracket and the mask shell in order to adjust for patient's of different sizes. A forehead support bracket is pivotally connected to the support arm. Likewise the chin support is also adjustably mounted to the mask shell.