The purpose of this work is to study the influence of the gas sparger on the hydrodynamics of bubble columns. Perforated plates, porous disc diffuser and flexible rubber spargers have been tested. The experiments were carried out on three bubble columns of the same height, 2m, and different inner diameters 0.08, 0.15 and 0.2 m. The experimental data obtained on these columns show that all the parameters which influence the hydrodynamic behaviour, depend strongly on the type of gas sparger and point out the special behaviour of the membrane disc diffuser. The critical gas flow rates corresponding to the transition from one gas flow regime to another, and bubble diameter have been determined. Different correlations are proposed to predict gas holdup and axial liquid dispersion coefficient values.