Effect of hypoxia on oxygen uptake at the gills in the abalone Haliotis（Nordotis）discus discus was examined with the direct measurement method of ventilation volume at 17℃. The ventilation volume and the oxygen utilization increased gradually with decrease of the oxygen partial pressure in the water from 199 ml/min/kgTW（total weight）and 62% to 392 ml/min/kgTW and 94%, respectively. The amount of oxygen uptake was maintained at the same level（0.758 ml/min/kgTW）until the oxygen partial pressure decreased to 90 mmHg, then was decreased gradually with decrease in the oxygen partial pressure.