For a chemical reaction of large exothermic or endothermicity when carried out-in fluidized beds, an internal heat transfer surface additional to the walls of the bed is often necessary. The heat transfer characteristics of vertical tubular inserts placed in the fluidized bed were examined by measuring the heat transfer from coils integral in the inserts to the fluidized bed. It was found that the heat transfer coefficients measured at the coils corresponded closely to the heat transfer coefficient for bulk heat transfer measured in open fluidized beds under non-slugging conditions. Variations in heat transfer over the array of inserts were small, and distributor effects were significant only at the onset of fluidization. The experimental results were successfully related to an earlier correlation given for heat transfer in open beds.