Natural fibers have been used since ancient times, but since the 20th century they have been largely substituted by synthetic fibers, which offer several advantages such as their homogeneous properties. However, in light of the growing concerns about sustainable development, natural materials have once again started to substitute synthetic ones. A few of the advantages of utilizing lignocellulosic fibers include biodegradability, low cost, and low abrasiveness. In recent years, among many applications, the civil construction and automotive industries are using natural fibers as reinforcement in thermoplastic composites, as well as interior cabins of cars and trucks and helmets used in PPE. Over the past years, areas such as civil construction and the automotive industry have used natural fiber-reinforced thermoplastic composites in car and truck interiors, as well as in helmets used in constructions. This work intends to characterize fibers available in the brazilian market, in particular: Etlingera elatior, Costus, Helicônia bihai. These three species are mainly used as medicinal plants or ornamental flowers, but there is a great potential to reutilize the discarded stems of these plants. Furthermore, these fibers will be characterized using digital microscopy and image analysis, aiming to measure their real transversal section. A method for preparing natural fiber samples will be developed for this purpose. For this was a characterization of the fibers was done in order to measure the true cross section of these using digital microscopy and image analysis. Besides it has been developed a methodology for the preparation of samples of natural fibers. Characterization was performed by SEM, XRD and TGA.