The combination of fibers with traditional reinforcement may be a very interesting design solution to achieve more durable and economical structures. This paper deals with the analysis of the aforementioned solution through the study at serviceability and ultimate limit states. For this purpose, a total of eighteen concrete slabs were produced (3x1x0.2 m) with different reinforcement configurations, types of fibers (steel and plastic) and the fiber dosage used (0.25 and 0.50%). These slabs were tested under the configuration of a four point bending test. The results of this experimental campaign were used in the study of the cracking and deflection of the various types of concrete, tackling the analysis from several points of view. ; Peer Reviewed ; Postprint (author’s final draft)