Phase holdup characteristics have been investigated in a gas-liquid-solid circulating fluidized bed(0.102m I.D×3.5 m in height). Effects of velocities of dispersed gas and continuous liquid phases and solid circulation rate on the individual phase holdup and its axial distribution in the bed have been determined. Compressed air and water have been used as a dispersed gas and a continuos liquid phase, respectively, while glass beads with the diameter of 2.1 mm have been used as a fluidized solid phase. It has been found that the gas holdup has increased with increasing dispersed gas velocity, but liquid velocity and solid circulation rate have little effect on the gas holdup. The liquid holdup has increased with increasing liquid velocity, however, it has decreased with increasing gas velocity and solid circulation rate. The solid holdup has increased with increasing solid circulation rate and gas velocity, whereas, it has decreased with increasing liquid velocity. The axial distribution of solid holdup has become uniform with increasing liquid velocity. The gas holdup and bed porosity have been well correlated in terms of operating variables such as gas and liquid velocities and solid circulation rate.