The fraction of soluble and insoluble fiber was determinate by AOAC International official method for dietary fiber in four varieties of Bamboo called Guadua Angustifolia Kunth. The elastic modulus of the four bamboo varieties was determined using an universal machine INSTROM 4401 based on the ASTM standard method D-143. Finally, the fiber content and the mechanical behavior were correlated using the Pearson coefficient calculated by statistical package STATGRAPHICS 5.1 The fiber content is the main factor responsible for the bamboo mechanical properties. The results show that the all fiber content into the bamboo culms is related with the mechanical behavior. These results confirm that the Guadua Bamboo is a natural composite material with aligned fibers embedded in a matrix formed by soluble fiber.