This survey determined the prevalence and regional distribution of mental retardation among children in Saudi ArabiData were analysed from a population-based national survey conducted during 1996-99, in which 60,630 children aged up to 18 years were screened using IQ tests and questionnaires completed by physicians. The prevalence of mental retardation was 8.9 per 1000 children, a rate similar to that reported in other countries. Moderate or severe retardation was classified in 70.9% of these children. Of the mentally retarded children in the 0-18 years age range, 83.2% were not attending school. Special educational programmes are needed to improve the quality of life of mentally retarded children.