A population-based survey of the prevalence and cause of blindness and poor vision was conducted in the Republic of Benin in 1990 using a stratified cluster random sampling procedure. The survey was designed and implemented through the collaboration of the Ministry of Health of the Republic of Benin and the Programme for the Prevention of Blindness of the World Health Organization (WHO/PBL). Survey data were analyzed at the International Centre for Eye Health, Institute of Ophthalmology, University of London, United Kingdom. In accordance with the procedures recommended by WHO/PBL, 7272 individuals were recruited and 7047 were examined. The survey achieved excellent coverage in all locations with an overall coverage of 96.9%. The prevalence of blindness (visual acuity less than 3/60 in the better eye) was 0.6% (CI95% = 0.4%-0.9%). The prevalence of poor vision (best vision less than 6/60 but not blind in the better eye) was estimated at 2.6% (CI95% = 2.1%-3.1%). The major causes of blindness were age-related cataract and glaucoma (54% and 15% respectively of blind people recruited). The major cause of poor vision were cataract, refractive errors, and macular disorders (64%, 9.6%, and 9.0% respectively of people recruited with poor vision. The survey results indicate that there is an urgent need for basic eye care services. Cataract has been designated as a priority target in the recently designed National Blindness Prevention Programme now being implemented in the Republic of Benin. With proper management of this problem, the current prevalence of blindness and poor vision could be reduced by at least 45%. At the end of this cluster study, the design effect (D = 1.56) and rate of homogeneity (ROH = 0.002) were computed for an average number of 250 people per cluster.