Two South-American plants, native Caranday Palm and Phormium, were characterized to investigate their potential as a source of fibers for the preparation of polymer composites. The plant leaves were subjected to different chemical characterizations, whose results were further corroborated by Fourier transformed infrared spectroscopy and Thermogravimetric analysis techniques. The results showed that leaves from Caranday Palm have higher cellulose content than Phormium leaves. The tensile testing of the technical fibers showed that they may be suitable for use in the production of polymer composites, as the properties are comparable to those of other vegetable technical fibers. Preliminary results on the effect of the incorporation of Caranday Palm fibers into polypropylene lead to a composite of improved modulus and relatively low density. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 2236-2245, 2010