The bed-to-wall heat transfer coefficients were measured in a circulating fluidized bed of FCC particles(d_p=65㎛). The effects of gas velocity (1.0-4.0 ㎧), solid circulation rate(10-50 ㎏/m²s)and particle suspension density(15_-100㎏/m³) on the bed-to-wall heat transfer coefficient have been determined in a circulating fluidized bed(0.1m-ID X 5.3m-high). The heat transfer coefficient strongly depends on particle suspension density, solid circulation rate, and gas velocity. The axial variation of heat transfer coefficients is a strong function of the axial solid holdup profile in the riser. The obtained heat transfer coefficient in terms of Nusselt number has been correlated with the pertinent dimensionless groups.