Simultaneous measurements of gas and liquid-phase velocities along with the gas hold-up can provide a wealth of information regarding the flow structure in bubble columns. Tn the present work, a method is proposed for simultaneous measurements of phase velocities together with the hold-up, using a laser Doppler velocimeter. The measurements were performed in a rectangular bubble column up to a hold-up value of 26%. Turbulence parameters, in particular, rms velocities of both the phases and length scales, were also determined.