Plastic / natural fiber composite foams offer the advantages of both the composite and foamed materials. In this research, the effects of the processing conditions and the concentration and type of CFA (chemical foaming agent) on the physical and morphological parameters of foamed HDPE / coffee husk composites were studied, with the objective of achieve continuous production of these materials in extrusion, using a CFA. Each step of the process is addressed, including the selection of materials, mixing, pelletization, and extrusion - foaming of the composite, and the characterization of relevant physical and morphological parameters of the obtained product. The greatest potential for this materials, is in building products that have limited structural requirements offering lower maintenance, high durability and lower environmental impact compared with the use of solid wood.