The effect of hypoxia on renal tubular function was measured in 2 dogs and 2 humans. No change in the ability of the kidney to absorb glucose or to secrete para-aminohippurate was seen during the inhalation of a 9.4% O2 in N2 gas mixture in man nor in the dog during inhalation of 9.4 or 6.3% O2 in N2 It is suggested that other abnormalities of tubular function seen in hypoxia are mediated indirectly rather than by direct depression of renal tubular metabolic activities.