AbstractInterfacial area is measured for a large range of column packing (Raschig rings, Intalox saddles, and two sizes of spheres) for concurrent gas–liquid upflow through packed bed covering bubble, pulse and early spray flow regimes using air–aqueous sodium sulfite solution. It was observed that the interfacial area increased with increase in fluids flow rate and decreased with the increase in the particle size for the same type of packing. A correlation (3 ≤ Rel ≤ 165, 0.5 ≤ Reg ≤ 210) was developed using present data (120 data points) and literature data (100 data points), which predict the interfacial area with an rms deviation of 16%.