Phormium tenax is a natural fiber of plant origin from New Zealand that adapts to equatorial, oceanic, subtropical and tropical climate. In this work it was used as reinforcement in the production of polypropylene (PP) based composites. With the intention of using this material for structural and semi-structural applications, samples of reinforced PP composites with different fiber contents and in some of them in the presence of an aluminum foil were mechanically tested. The fibers used are in natura in short, 5 mm, long, 50 mm and continuous lengths (160, 125 and 63 mm) and the composites were submitted to tensile, bending and impact tests. Samples were made in extrusion and compression processes and also only by compression. Phormium tenax, composites, PP and malleated polypropylene (PPMA) were characterized chemically and thermally. Morphological and mechanical analysis of Phormium tenax were performed. Qualitative aspects were evaluated in composites. Results point to a good mechanical resistance of the fiber under study, however they do not demonstrate good efficiency in the reinforcement of PP, requiring adjustments in obtaining the composites.