Cerebral blood flow (CBF) was compared during conventional low frequency ventilation (LVF) [tidal volume 15 ml/kg, respiratory rate 12] and high frequency ventilation (HFV) [tidal volume 3 ml/kg, respiratory rate 100] in normal cats. The intra-arterial 133Xenon technique was used to determine CBF. No significant difference in CBF was present between the 2 groups. The mean CBF was 46.6 ± 14.2 ml/dl.min during LFV and 44.4 ± 12.2 ml/dl.min during HFV. Additionally, mean arterial pressure, CVP, intracranial pressure (ICP), cerebral perfusion and airway pressures were not significantly different between the groups. HFV has little effect on cerebral hemodynamics.