Anterior tooth crown fracture in children is something that each dentist will confront many times during his professional career.We studied the prevalence of anterior teeth crown fractures between 7-14 years old students in Tehran and some relevant factors like sex, age, the traumatized tooth, amount of overbite and overjet, upper lip coverage, jaw that had fractured tooth or teeth and place of fracture in fractured crown.1338 boys and 1184 girls were in this study. Tooth fracture was almost the same in boys and 1184 girls with the prevalence of 8%. Fracture was mostly in enamel and average year of fracture was 10 years.Increased overjet and overbite had direct relation and indirect relation with fracture, also enough lip coverage showed less fracture.