Background: visual impairment is one of the commonest causes of disability globally. Uncorrected refractive error is the commonest and largely preventable cause of avoidable visual impairment worldwide. The objective of this study is to ascertain the distribution of refractive errors in the adult populations in Ogun state, southwestern Nigeria. Methods: This is a retrospective review of adults from 18 years and above. Data was collected from the patients’ case notes from January 2008 to December 2012 from the record department of Deseret Community vision institute (DCVI) in Ogun state, Southwestern Nigeria. The diagnoses used are: myopia, hyperopia and astigmatism. A systematic sampling of 1000 patients from 6000 case notes was done. Specific information that was retrieved include: age, sex, town of residence, entry or unaided visual acuity, degree of refractive error and corrected visual acuity. Myopia is regarded as ≥ -0.50DS, hyperopia ≥ +0.75DS, astigmatism ≥ - 0.25DC and emmetropia: > - 0.50 - < + 0.75. All statistical analysis was done by statistical software STATA 11.0. Results: Of the 446 with refractive error, 191(42.82%) were males, 255(57.18%) were females. Age range is from 18-88. Mean age was 48.2. Astigmatism is the commonest cause of refractive error 289(64.80%), followed by hyperopia 96(21.50%) and myopia 61 (13.70%). Females have more refractive errors than males. Age, sex and occupation are not statistically associated with refractive errors. Conclusion: Refractive errors are common eye conditions and astigmatism is the commonest type of refractive error in adults. Females have more refractive errors than male.