Tests were carried out on 63 healthy persons aged 17–29 years, in the sitting position. The following parameters of lung ventilation were determined: Vd, phys/ Vt=30±0.6%,AaDO2=10±0.9 mm Hg, aADCO2/paCO2 was equal to the end-expiratory pCO2, i.e., to Pet,CO2=5.0±0.4 mm Hg,\(\dot Qva/\dot Qt\) (air)=2.3±0.3%,\(\dot Qs/\dot Qt\) (O2)=1.8±0.2%. For the lungs as a whole\(\dot VA/\dot Qc\) was normal (0.86±0.30). No difference in\(\dot VA/\dot Qc\) could be found between men and women. The main contribution to the development of\(\dot Qva/\dot Qt\) in healthy subjects belongs to the anatomical shunt and perfusion of unventilated alveoli.