The electrical conductivity of metallic foams varies strongly with porosity. Data are presented for replicated open-pore microcellular metal over a wide range of relative density. These data, together with data from the literature for different foam structures, are compared with previously suggested models for the conductivity of porous materials. We show that clear differences exist between the behavior of foams according to their different structural types and that simple models exist to capture these differences. (c) 2006 American Institute of Physics.