Purpose: To evaluate and compare the efficacy of impregnation procedures on the flexural strength of polypropylene fibers reinforced polymethyl methacrylate (PMMA) denture base material. Materials and methods: Eighty PMMA samples of dimensions 65 mm × 10 mm × 3 mm were fabricated after different treatments as control group C (n = 20) and three test groups: silanized polypropylene fibers T₁ (n = 20) (fibers treated with silane coupling agent), polypropylene fibers soaked in monomer T₂ (n = 20) (fibers treated with monomer), and silanized polypropylene fibers soaked in monomer T₃ (n = 20) (fibers treated with silane coupling agent and monomer). Samples were subjected to flexural loading using a universal testing machine. Flexural strength was evaluated using the Kruskal–Wallis test and multiple analysis was done by Mann–Whitney post hoc analysis tests. Results: Mean flexural strength values obtained from different groups demonstrate that test group T₃ (silanized polypropylene fibers soaked in monomer) exhibits higher flexural strength (0.325 ± 0.021 N/mm²) followed by test group T₂ (polypropylene fibers soaked in monomer, 0.221 ± 0.009 N/mm²) and control group C (0.141 ± 0.011 N/mm²). Test group T₁ (silanized polypropylene fibers) showed the lowest mean flexural strength (0.070 ± 0.008 N/mm²) among all the study groups and the difference was statistically significant (p < 0.001). Mann–Whitney post hoc analysis showed that there was a significant difference between all groups. Conclusion: Based on the results of the present study, silanized polypropylene fibers showed the lowest mean flexural strength. When silanized polypropylene fibers soaked in monomer their flexural strength increased. In instances of anticipated fracture of dentures, impregnation procedures and addition of polypropylene fibers would be help to minimize them.