Experimental measurements of gas holdup and liquid axial dispersion coefficients have been carried out in two bubble columns (column I; D-c = 15 cm and column II; D-c = 20 cm), operating with co-current upflow of gas and liquid. In addition, measurement of bubble size was investigated. Peclet number and liquid axial dispersion coefficient were calculated from the means and variances of the residence lime distribution (RTD) curve. The experimental data obtained show that the hydrodynamic of bubble column depends on superficial gas and liquid velocities, column diameter and the gas flow regime. Present results and the available literature data were used to develop a model involving Bo, Re, Fr and Ga for predicting liquid axial dispersion coefficient.