Gas exchange and pulmonary mechanics in high frequency-jet ventilation (HFJV) were studied during intubation anesthesia in patients with normal respiratory organs. The HFJV frequency ranged from 100 to 400 per minute. The tidal volumes (VT) varied from 50 to 140 ml. Gas exchange was studied in 11 patients, the total number of regimens amounting to 69. The physiological dead space volume (VD) was determined by the Bohr method for different combinations of VT and frequency after 15-minute ventilation with each regimen. The values of VD and VA were found to have linear relationships with VT and no relation to the ventilation frequency. Linear regression equations were derived for these relationships. The dynamic pulmonary distension in HFJV was assessed in 9 patients using the interrupted HFJV techniques, up to 28 regimen being tested for each patient. An exponential relationship between the accumulated gas volume and VT was found at fixed frequency values and duration of the expiratory phase. The regimen capacity for inducing gas accumulation in the lungs is determined by the ratio of ventilation frequency to the expiration time (accumulation coefficient). The dynamic pulmonary distention in HFJV is attended with a rise in mean respiratory pressure which, however, remains lower than the mean alveolar pressure. The obtained evidence should be taken into account when choosing an optimal regimen for individual HFJV.