Face mask ventilation is a basic skill taught to and practised by a large array of medical practitioners. It is usually the first technique applied to an unconscious patient or victim that is unable to generate effective oxygenation and ventilation. Although it is considered a simple technique its outcome is often suboptimal. This chapter describes face mask ventilation devices, techniques and the concept of difficult face mask ventilation. The one- and two-hand face mask ventilation are reviewed in the context of the airway manoeuvres used to address the upper airway obstruction of the supine unconscious patient: head extension, jaw thrust and the triple airway manoeuvre. The concept of measuring the adequacy of face mask ventilation using known objective ventilation outcome markers (tidal volume, airway pressure and the capnogram) is introduced to contrast with the routine unreliable subjective markers (cyclical condensation of the mask dome and bag compliance). Reassessment of face mask ventilation technique using objective ventilation markers is encouraged to further optimisation of the outcome. The predictors and the management of face mask difficulty is examined from a practical point of view.