For enriching the heat transfer coefficient database of refrigerants flow boiling in metal-foam filled tubes, the heat transfer characteristics of two-phase flow in horizontal metal-foam filled tubes were investigated for flows in small diameter tubes and at higher mass fluxes. The results show that the heat transfer enhancement due to metal foam at lower mass fluxes is about 50% greater than that at higher mass fluxes. A flow pattern based prediction method was developed for a much wider range of working conditions than previous ones. The influence of the metal foam on the flow pattern and heat transfer area increase is both considered in the new prediction method. The heat transfer coefficients predicted by the correlation agree well with experimental data from the present and previous studies. (C) 2015 Elsevier Ltd. All rights reserved.