Measurements of neutron number albedos for double-layered slabs are made using a collimated beam of fission neutrons from a 252Cf source. The dependence of the number albedos on the first layer thickness is examined and compared with that for single-layered slabs. It is shown that the difference between the number albedos of one- and two-layered slabs is very large and that the albedos change exponentially with the thickness of the first layer.