The Current Work Evaluates the Potential of Computed Tomography (CT) Measurements for Flow Regime Characterization. Experiments Were Carried Out in a Pilot Scale (0.162 M Diameter) Bubble Column using an Air-Therminol LT System at Ambient as Well High Operating Pressures (0.4 and 1MPa). the Superficial Gas Velocities Were Varied From1 to 20 Cm/s at Intervals of 1 Cm/s. the Steepness of the Gas Holdup Radial Profile Was Analyzed to Demarcate the Hydrodynamic Flow Regime. the Regime Transition Velocities Obtained from CT Measurements Are Compared with the Drift Flux Model. an Increase in Operating Pressure Was Found to Delay the Regime Transition and at Higher Pressures, a Transition Occurred over a Range of Superficial Gas Velocities. the Current State of Correlation Prediction is Evaluated Against the Experimental Transition Velocities. © 2005 Published by Elsevier Ltd.