Immediately after birth through spontaneous breaths, infants' clear lung liquid replacing it with air, and gradually establishing a functional residual capacity to achieve gas exchange. Most infants start breathing independently after birth and ~3% of infants who require positive pressure ventilation. When newborns fail to start breathing the current neonatal resuscitation guidelines recommend initiatingpositive pressure ventilationusing a face mask and a ventilation device. Adequate ventilation is the cornerstone of successful neonatal resuscitation; therefore, it is mandatory that anybody involved in neonatal resuscitation is trained in mask ventilation techniques. One of the main problems with mask ventilation is that it is very subjective with direct feedback lacking and not uncommonly, the resuscitator does not realise that their technique is unsatisfactory. Many studies have shown that monitoring tidal volume and leak around the mask or endotracheal tube enables the resuscitator to identify the problem and adjust their technique to reduce the leak and deliver and appropriate tidal volume. This chapter discusses the currently available monitoring devices used during stabilization/resuscitation in the delivery room.