The prevalence and causes of blindness and visual impairment were determined in Yewa-North local government area of Ogun state, Nigeria between May 15 and June 22, 2001. A population - based survey using a random cluster sample of 1,964 persons representing usual residents of the local government area was examined. The survey revealed that 1.22% of the populations were blind, 1.43% unilaterally blind and 2.09% were bilaterally visually impaired. Blindness and visual impairment were found in persons aged 45yrs and above. Blindness was found to be 2.43 times commoner in men, which was statistically significant. Cataract was the commonest cause of blindness accounting for 37.5% of blindness and 36.6% of visual impairment. Another important cause of visual impairment and blindness in this study was pterygium accounting for 23% and 19% of unilateral and bilateral visual impairment and 7% and 4% of unilateral and bilateral blindness respectively. The report showed that 87.5% of the blindness and 75.7% of the bilateral visual impairment were avoidable. These largely agreed with the pattern and causes of blindness in other parts of sub-Saharan Africa.