In this investigation, structural type mortars reinforced with corn fibers were elaborated; these fibers were previously treated with flaxseed oil and paraffin, cut to lengths of 1, 2 and 5 cm, and weighed, in order to obtain a ratio of 0.5% and 1% by weight with respect to the quantity of cement.The fibers were physic chemically characterized by Thermogravimetric Analysis (TGA), Derivative Thermogravimetry (DTG) and Fourier Transform Infrared Spectrometry (FTIR), and their chemical resistance was evaluated by exposing them to a concentrated solution of Ca(OH)2 that simulated the alkaline medium of the cement.The fiber-reinforced mortars were mechanically characterized by compression and bending tests, which were performed 7, 21 and 28 days after processing.The results show that after 28 days the paraffin-coated corn fiber reinforced mortars, with 1 cm in length and 0.5% in weight presented the best results, an increase in the compressive and flexural strength of 16.92% and 38.51% respectively was noted, compared to the unreinforced mortar.