Objective: The aim of this study was to measure and report the pupillary diameter of myopic refractive surgery candidates and to identify the associated factors.Methods: This was a retrospective, descriptive, cross-sectional study. Consecutive patients withmyopia or myopic astigmatism were included in the study. Patients with accompanying ocular pathologies were excluded. Only one eye of the remaining patients was selected using a randomnumber table. Age, sex, spherical equivalent of manifest refraction (SE), and axial length (AL) wererecorded. Scotopic, mesopic, and photopic pupillary diameters were measured with dynamic pupillometery (Sirius, Schwind Eye Tech Solutions AG, Germany).Results: Eighty eyes of 80 patients were included in the study. The mean age of the patients was 28±6years, and mean SE was -5.25±2.26 D. The mean AL was 25.41±1.41 mm. The mean scotopic, mesopic,and photopic pupillary diameters were 6.26±0.60, 5.81±0.61, and 4.43±0.68 mm, respectively. SE andAL were not found to be correlated with pupillary size. The mesopic pupillary diameter was slightlyhigher in females than in males (5.98±0.50 vs. 5.62±0.68; Student t test; p=0.037). There was a statistically significant negative correlation between mesopic and scotopic pupillary diameters and age.Conclusion: This study investigated the pupillary diameters of myopic refractive surgery candidates and showed that age and sex are the most important determinants of pupillary diameter.