Gas holdup has been measured in an 83-mm diameter, 2.2-m high column at high gas superficial velocities - 0.22 to 2.7 m/s -and at liquid (water) superficial velocities of 0 to 0.47 m/s, by means of a differential pressure transducer. The equation of Hills (1976) based on the slip velocity gives good predictions of the gas holdup for 0.1 less than or equal to epsilon (g) less than or equal to 0.4. However, the holdups predicted by this approach are considerably higher than the experimental values at gas velocities high enough that epsilon (g) > 0.4. Other equations from the literature are also shown to be inadequate. The new data and earlier data at high gas velocities are therefore correlated with a new dimensional equation for U-l less than or equal to 0.23 m/s.