PURPOSE: To determine the prevalence and pattern of congenital colour vision defects among secondary school students MATERIALS AND METHODS: A descriptive cross sectional study conducted between October and December 2012.. A multistage sampling was used to pick a representative sample of students in public co-educational senior and junior secondary schools in Ibadan North Local Government Area.All students who met inclusion criteria had visual acuity assessment, ocular examination, Ishihara colour test and an interviewer administered questionnaire was given to collect information on socio-demographic data, previous ophthalmic history and performance at colour related task in school and in activities of dailyliving. Assessment with Farnsworth-Munsel D-15 panel was done for all students who failed the Ishihara test.