Background: Today the acrylic resin, namely polymethyl methacrylate (PMMA), occupies a prominent place in the spectrum of denture base materials. PMMA as a denture base material is not ideal in many aspects. The primary problem is its poor strength characteristics, including low impact and flexural strength. Aim and Objectives: The purpose of this study was to evaluate the flexural strength of heat cure denture base resin reinforced with 3 different fibers. Objectives were to evaluate the flexural strength of heat cure denture base resin reinforced with glass fibers, to evaluate the flexural strength of heat cure denture base resin reinforced with nylon fibers, to evaluate the flexural strength of heat cure denture base resin reinforced with polypropylene fibers, to compare the flexural strength of heat cure denture base resin reinforced in all three groups and to compare the flexural strength of unreinforced group with other three groups. Materials and Methods: A total of 80 specimens of similar dimensions were prepared for each of the three experimental groups including control group (20 each). Group A was control group, Group B was reinforced with glass fibers, Group C was reinforced with nylon fibers and Group D was reinforced with polypropylene fibers. FS was evaluated with a three point bending test. The results were analyzed with a one way analysis of variance. Results: All reinforced specimens showed better FS than the conventional acrylic resin. Specimens reinforced with glass fibers showed the highest FS, followed by nylon fibers.