Aim: To assess the magnitude of refractive errors in the school going children of the urban population of Kolkata, West Bengal and to study its age and sex distribution, types, distribution and the possible factors associated with them. Study Design: The study was a review of school based vision screenings conducted from 2005-2009. Materials and Methods: Survey of Refractive Error in school going children in the age group of 5-14 years and studying in class I to class VIII was done in 42 schools in and around Kolkata. Results: 16,597 school students were screened. Number of students detected with refractive errors was found to be 1,615 (10.2%). Out of the refractive error detected Myopia accounted for 58.2%, Hypermetropia for 17.7% and Astigmatism for the remaining 16.3%. Conclusion: Uncorrected refractive errors constitute a major public health problem in urban school aged children in and around Kolkata with myopia being the most common and early detection and timely intervention can easily eliminate these treatable causes of visual impairment.