Different countries in the world still use asbestos reinforcement for fibercements. For health reasons, the trend is to replace the asbestos for polymeric materials readily available in the regions. The bamboo´s mechanical properties and good accessibility around the world have motivated the exploration of this cellulose source as reinforcement of fibercement composites. Past researches have shown goodness in natural and synthetic polymers mixtures (cellulose and PVOH) to supply the requirements of this kind of compounds (Coutts, 1983), (Juárez, 2002), (Morán, 2008), (Khorami, 2011). In the present work, it have been performed fibercement compounds based on the methodology proposed by Khorami (2011) with cellulose extracted from bamboo, employing two different refining techniques, three fiber length levels (0.60-0.15, 1.18-0.60 and 2.38-1.18 mm), and four mass ratio levels (2, 6, 10, 16 %W). Flexural properties and microstructures of the fracture surface, observed in a SEM, were evaluated. It was perceived a relationship between the processes and mechanical properties which shows that the more direct reactants exposure of the fibers creates stronger cement. Additionally, lower percentages and short length of bamboo shows improved mechanical properties (flexural and rupture modulus) and good adhesion between fiber and matrix. Keywords: Bamboo, Fibercement, Fibers, Composites. Biblyography Alvarado, C. A. (2002). Uso de fibras naturales de lechiguilla como refuerzo en concreto. Ingenierías, Vol. VII, No. 22. Coutts, R. (1983). Flax fibres as a reinforcement in cement mortars. International Journal of Cement Composites and Lightweight Concrete, 257–262. Juárez, C. (2002). Concretos base cemento portland reforzados con fibras naturales (Agave lechiguilla). México: Universidad Autónoma de Nuevo León. Khorami, M. (2011). Application of Natural and Synthetic Fibres as a Replacement for Asbestos Fibres in Cement Boards. Coventry University.