This study was done to Estimate developmental age for group of Egyptian children and adolescence using Mörnstad method for age estimation based on metric measurement of crown height, apex width, and root length during tooth development. The sample consisted of 120 panoramic radiograph of Egyptian healthy children (52 boys and 68 girls) with age range 6-14 years .when age estimation was done by Mörnstad et al. method, there was no significant difference between chronological age and developmental age in all age group 6-14 years with r=0.031 and p=0.735.