OBJECTIVE: To determine the frequency, types and distribution of refractive errors among public secondary school students in Lagos State, Nigeria. STUDY DESIGN: Descriptive cross sectional randomized study conducted from October 2005 to January 2007. METHOD: Randomly selected students in 19 public secondary schools within the 6 education districts in Lagos State constituted the sample. The study in all the schools was preceded by ocular health education. Bio-data and medical history were recorded on interviewer-administered, pre-tested questionnaires. Detailed ocular examination carried out included visual acuity measurement with multiple alphabetical Snellen’s chart, ocular motility evaluation, anterior segment examination with bright pen torch and magnifying loupe also, the posterior segment with Keeler’s Vista direct ophthalmoscope. Non cycloplegic objective refraction was performed on all subjects using Keeler’s Vista streak retinoscope followed by subjective refraction. Significant refractive error was defined as visual acuity of 6/12 or worse, or any error correctable with spherical equivalent of at least -0.500DS or +2.00DS, according to the guidelines of Refractive Error Study in Children (RESC). Exclusion criteria for refractive error included students with associated ocular pathologies such as retinal scar and lens 2 opacity. Prescription were given for glasses when indicated to be procured by parents or guardians. Data analysis was done with Statistical Package for Social Sciences, (SPSS) Version 11. Tests of association between variables were done using the chi-square test and when necessary Yates’ correction; p-values < 0.05 were considered statistically significant.