Usage of aqueous foam flow as a coolant allows relatively large heat transfer intensity with very small coolant mass flow rate in foam apparatus and heat exchangers. Our previous experimental investigation of the heat transfer between a vertical flat surface and longitudinal upward aqueous foam flow showed dependence of the surface cooling intensity on the foam flow velocity and the volumetric void fraction. In the case of an inclined flat surface, liquid drained from the foam and formed a film on the inclined heated surface. The direction of movement of liquid particles in this film depended on experimental conditions. An experimental investigation of the heat transfer between a horizontal flat surface and longitudinal foam flow was performed and the results are presented and discussed in this paper. It was observed that the particles of drained liquid film moved in the same direction as the foam flow. The cross-sectional velocity distribution of the foam bubbles influenced on the amount of draining liquid across the channel. Higher inflow of draining liquid of lower temperature gave rise to better conditions for the cooling of the side parts of the heated surface. (C) 2018 Elsevier Ltd. All rights reserved.