Heat transfer from a solid surface to a fluid-solid suspension in vertical or horizontal transport is of importance in the design of heat-exchangers, driers, fluidized beds, and slurry pipeline reactors. There are fewer studies on heat transfer in liquid-solid flows than on gas-solid flows. In this paper, a correlation for heat transfer to dilute liquid-solid flows in a horizontal pipe is presented. Suspension properties were used to derive the following equation: Nu(s) = 0.202Res0.6Prs0.675(D/d(p))0.092(mu(s)/mu(w))-1.95 This correlation can be used to estimate the heat transfer coefficients of liquid-solid two-phase flows for the following ranges of variables: Reynolds number Re(s), 27 000-120 000; Prandtl number Pr(s), 2.1-3.4; the ratio of suspension viscosity to the viscosity of water at the wall temperature mu(s)/mu(w), 1.17-1.83; the ratio of pipe diameter to the particle diameter D/d(p), 182-512; volume fraction of solids in the feed slurry C(f), 0.005-0.03. The accuracy of the correlation is approximately +/-20%.