This paper presents systematic studies carried out on the processing and characterization of continuous and aligned curaua fibers-polyester composites. Laminates of these composites with (0 to 40 vol. %) curaua fibers were press-molded at room temperature, cured for 24hours and tested for strength properties. Resulting fracture surfaces were analyzed by scanning electron microscope. Composites showed high flexural properties, which is attributed to a complex mechanism of individual interaction of the microfibrils with the matrix during crack initiation and further propagation through a model of stress concentration due to the specific fiber/matrix interface geometry. Impact test results showed a remarkable increase in the notch toughness with the amount of incorporated curaua fibers, which is attributed to the difficulty of breaking down the fibers and preferential de-bonding of the fiber/matrix interface, which in turn contributes to an elevated absorbed energy.