Statement of Problems: Dental age can be estimated on the basis of the tooth mineralization level during the developmental process of the teeth. Among various radiological methods reported for the dental age determination in children, Demirjian method is widely used.Purpose: To evaluate the applicability of Demirjian method in age estimation of the children aged 7-15 years in Babol, a northern city of Iran.Materials and Method: A cross sectional study was performed on the panoramic radiographs of 168 individuals with 7-15 years old. Maturation of the seven permanent teeth on the left side of the mandible was determined according to the crown and root development stages; described by Demirjian method. The mean of the dental age (DA) according to the Demirjian was compared to the mean of chronological age (CA). Data were collected and analyzed using SPSS, V18. P-values<0.05 were considered significance.Results: The mean and the SD of CA was 11.06±2.29 (boys: 11.08±2.31, girls: 11.03±2.28). The mean and the SD of DA was 11.44±2.85 (boys: 11.81±2.93, girls: 11.08±2.73) and the mean and the SD of DA minus CA for all of the children were 0.38±1.24 (boys: 0.72±1.2, girls: 0.05±1.21). Also, t-Test analysis showed the differences of the mean value of the estimated - chronological age difference was statistically significant between the boys and the girls group (p< 0.001).Conclusion: Considering the determined differences between estimated dental age and chronological age in this study; Demirjian method can be applicable for estimation of dental age in girls and boys before their puberty in northern of Iran.