Hydrodynamic characteristics of a gas-liquid reactor equipped with a gas-inducing impeller were investigated. Four different impeller designs and two different ring spargers were used. The effects of superficial gas velocity, liquid submergence, and the interimpeller clearance on the critical impeller speed for gas induction, the rate of gas induction, and the fractional gas hold-up were investigated. The critical impeller speed was found to increase with an increase in the superficial velocity of the sparged gas. It was also affected by the lower impeller design and the sparger size. The rate of gas induction was found to decrease with an increase in the superficial gas velocity. It also depends on the lower impeller design and the sparger size. The liquid submergence had an optimum value at which the rate of gas induction was a maximum. The data obtained could be successfully correlated on the basis of mathematical models developed earlier.