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ABSTRACT Background and Aim: Since no study on the prevalence of refractive errors had been performed in this optometry clinic, this study was designed to determine the prevalence rate of refractive errors among the patients examined in this clinic in 2008/2009. Materials and Methods: In this cross-sectional study, the files of the patients examined in optometry clinic in 2008/2009 were reviewed. Variables included age, sex, rate and type of refractive errors and health of anterior and posterior eye segments. Results: The prevalence rates of myopia, hypermetriopa, astigmatism and emmetropia were 11.83%, 15/38%, 45%, 27/34% respectively. The respective prevalence rates of refractive errors in men and women were: 10/3% and 13/1% for myopia, 16.7%, 15.1% for hypermetropia, 45.6% and 44.5% for astigmatism, and 27.4% and 27.3% for emmetropia. The mean ages of the patients with myopia, hypermetropia and astigmatism were 36.1±19.36, 41.27±22.06 and 32.16±20.98. Respectively Difference of the ratios of the patients with different ages suffering from refractive errors was significant (P<0.0001). There was no significant difference in the male to female ratio in the patients with refractive errors (P<0.741). Conclusion: This study showed that the prevalence rate of myopia increased up to the age of 20-30 years but that of hypermetropia decreased, and prevalence rates of myopia and hypermetropia in some age groups increased after the age of 40. In addition, the prevalence rates of refractive errors in different age groups were not similar and gender had no effect on the prevalence of refractive errors. These results are compatible with the results of other studies. Key words: Refractive error, Myopia, Hypermetropia, Astigmatism, Age and sex. Conflict of Interest: Nill Received: May 24, 2010 Accepted: Oct 14, 2010