This epidemiological study estimated the prevalence of Specific Language Impairment (SLI) in monolingual English-speaking kindergarten children. The study used a stratified cluster sample from rural, urban, and suburban areas in the upper Midwest, screening 7,218 children, with a language screening failure rate of 26.2%. A diagnostic battery was administered to both the screened failures and a similar number of controls, resulting in an estimated overall prevalence rate of 7.4%. The prevalence was 8% for boys and 6% for girls. Variations in prevalence were found among different racial and cultural backgrounds, but these differences were correlated with parental education, which was also associated with SLI. Parents of 29% of the children identified as SLI reported being previously informed about their child's speech or language problem. The study's findings suggest that SLI is more prevalent among females than previously reported and that clinical identification of these children remains low. The prevalence estimates fall within recent estimates for SLI but highlight the condition's higher prevalence among females and the need for better identification methods.This epidemiological study estimated the prevalence of Specific Language Impairment (SLI) in monolingual English-speaking kindergarten children. The study used a stratified cluster sample from rural, urban, and suburban areas in the upper Midwest, screening 7,218 children, with a language screening failure rate of 26.2%. A diagnostic battery was administered to both the screened failures and a similar number of controls, resulting in an estimated overall prevalence rate of 7.4%. The prevalence was 8% for boys and 6% for girls. Variations in prevalence were found among different racial and cultural backgrounds, but these differences were correlated with parental education, which was also associated with SLI. Parents of 29% of the children identified as SLI reported being previously informed about their child's speech or language problem. The study's findings suggest that SLI is more prevalent among females than previously reported and that clinical identification of these children remains low. The prevalence estimates fall within recent estimates for SLI but highlight the condition's higher prevalence among females and the need for better identification methods.