An ergonomic chin support is designed for use in combination with medical headgear. The headgear has flexible straps adapted for locating a ventilation interface on a patient. The ergonomic chin support comprises a generally arcuate and substantially rigid chin cradle. First and second substantially rigid extensions are formed at opposite ends of the chin cradle, and are adapted for being pulled by respective straps of the headgear to urge the chin cradle against the mandible of the patient. Retaining posts are provided for retaining the ergonomic chin support at a fixed location along respective lengths of the straps.