Heat transfer chracteristics of two(liquid-gas, liquid-solid)and three(liquid-gas-solid)phase fluidized beds have been studied in a 15.2cm-ID column fitted with an acially mounted cylindrical heater. Effects of gas velocity (0-12cm.s), liquid velocity (0-16 cm/s)and liquid viscosity (0.001-0.039 Pa.s) on heat transfer coefficient were determined. The heat transfer coefficient increased with fluid velocities and particle size and it decreased with liquid viscosity in two and three phase fluidized beds. The bed porosity at which the maximum heat transfer occurred decreased with particle size but increased with liquid viscosity. The coefficient were correlatedd in terms of experimental variables. Mdified Nusselt number from the present and previous sudies has been correlated with modified Prandtl and Reynolds numbers.