Concrete is one of the most used materials in the world. Since its first appearance in combination with steel reinforcement, in the XIX century, concrete has evolved significantly, and can nowadays be considered as an "engineered material". For example, although this material is inherently brittle, it has already been possible for several decades to modify this behavior through the addition of fibers. And even in the field of fiber-reinforced concretes (FRC) it is difficult to generalize: there are natural, synthetic, and steel fibers; fibers for structural purposes and anti-shrinkage fibers; micro fibers and macro fibers and so on. This study focuses on fiber-reinforced concretes with synthetic structural fibers, whose main contribution is to significantly increase the ductility of the material. Three different types of fiber are considered in this study: classical twisted fibers, commonly used in practical applications, and two new types of straight fibers, one characterized by the presence of special surface texture and the other by the simultaneous presence of special prints and longitudinal stiffeners. In particular, the effect of different fiber dosage (2, 3 and 4 kg/m3) and different fiber length (40, 50 and 54 mm) on the flexural behavior and the compressive strength of FRC is investigated. Three point bending tests, with a span length of 500 mm, were carried out by controlling the crack mouth opening displacement (CMOD), according to UNI EN 12350-2 standard. As expected, the results highlight that flexural behavior (residual flexural strength at different CMOD values) improves as the dosage increases for each series of fiber-reiforced concrete investigated. Interestingly, comparison of different types of fibers highlights better flexural behavior in the case of fibers with special prints and, even more so, in those with special prints and flexural stiffeners. This could be justified by better adhesion between these types of fibers and concrete, preventing detachment and horizontal sliding.