Background: To assess the effects of complete dentures on respiratory performance. Materials & Methods: A total of 20 participants were included in the study. All the necessary spirometry examinations were conducted. The measurements taken during the spirometric assessment included Forced Vital Capacity (FVC), Peak Expiratory Flow (PEF), Forced Expiratory Volume in 1 second (FEV1), and FEF 25–75. Results: The spirometric measurements for FVC, PEF, FEV1, and FEF 25–75 were taken under different conditions. During Stage 1, where no dentures were worn, the recorded values were 3.10, 5.80, 2.48, and 2.75, respectively. Conclusion: There was a significant decrease in the value of spirometric variables in the presence of dentures. Keywords: spirometry, Complete dentures, forced vital capacity