Background and aims: Evaluation of oral health in children plays an important role in determining the health status. This study، simultaneously with the comparison of different provinces in terms of Oral Health at Beginning of Primary School، determines the impact of socioeconomic factors on the oral health of children. Methods: The study was descriptive-analytic and cross-sectional and using information from 7768 primary school children، who were referred to Children Health Testing centers in all provinces of Iran، in the academic year of 2016. To analyze the results، SPSS software and Chi-square test applied. . Results: From 7768 kids، 33. 7% of the beginners were in a healthy oral status and 66. 3% had an unhealthy oral status. The highest percentage of beginners with oral health problems were in South Khorasan provinces with 90. 1%، West Azarbaijan، 88. 2% and Markazi with 86%. The percentage of children with oral health problems in rural areas is higher than cities (p<0. 001). Increased mother's education (p <0. 001)، increased father's education (p <0. 001)، lack of mother's employment (P> 0. 05)، basic insurance (P <0. 05)، supplementary insurance (p<0. 001) and increase in income (p <0. 001) have a positive and significant effect on improving oral health of children. Conclusion: According to the study، the low level of education of parents، especially the mother and the habitat in the village، affect the oral health of children. Due to the young population of the country، planning for the prevention and treatment of children's oral teeth is essential.