PURPOSE: To determine the prevalence of stuttering among primary school children in Cairo. METHOD: A cross-sectional design was employed. Using a multi-stage random sample from 10 schools in Cairo, a total of 8765 primary school students were enrolled in the study. The teacher referring method was initially used to detect stuttering students, which was then confirmed by a Speech Language Pathologist (SLP) using Diagnostic and Statistical Manual for Mental Disorders-Fourth Edition (DSM-IV) criteriPersonal data were collected for all students and separate questionnaires were administered to the parents of each stuttering child, inquiring about consanguinity, family history, presence of other disorders and family attitudes towards the child. RESULT: Prevalence of stuttering among primary school children in Cairo was 1.03%. The prevalence of stuttering showed a declining trend in the older age group. Stuttering was 7-fold more prevalent among left-handed students. Males had a higher prevalence of stuttering, but didn't reach statistical significance. Anxiety was expressed in 25% of the families of affected children. Positive family history was found in 28% of cases, mainly among first-degree relatives. CONCLUSION: The current study showed a prevalence of stuttering comparable to other areas of the world with some evidence of hereditary background, although lower than that reported by other studies.