Treatment of acute respiratory failure is still a hot issue in intensive care everyday practice: in the last few years high frequency ventilation techniques have been employed as a therapy for adult respiratory distress syndrome (ARDS) and acute respiratory failure (ARF). We applied high frequency percussive ventilation (HFPV) to 3 patients affected by ARDS or ARF, who did not improve after 24 hours of conventional mechanical ventilation (CMV). All our patient underwent 12 hours of HFPV, and showed an improvement of both respiratory exchange and radiological imaging. Even if the pathogenesis of ARF was quite different, in all patient we registered a good response and no complications.