The prevalence and type of congenital cleft of the lip and palate in mongolia, affiliation of the patients Background: The prevalence of congenital cleft lip and palate is different internationally. There are some research papers which identifying the rate of this abnormality in Mongolia, the latest one shown the result that one cleft case for 1072 live births (Ayanga GN et all, 2012). Aim: to determine/update the prevalence and types of congenital cleft lip and palate in Mongolia Materials and methods: we include the data from all cleft patients who were born between 01 of January, 2011-31 of December, 2021 to this survey retrospectively. We used the e-history for cleft patients, which developed by the department of Maxillofacial surgery since 2011. Results: Totally 1308 cleft patients included to our survey. The prevalence is one cleft cases for 652 live births in Mongolia, and 34,1% is cleft of the lip, 41,4% is cleft of the lip and palate, and 24,5% is cleft palate only of all cases. Also the rate was differently among provinces, as one for 429 live births in Khuvsgul province, and one for 1223 live births in Uvs province. Conclusions: the prevalence of cleft lip and palate in Mongolia 1000:1.5 or one for 652 live births. The highest rate established in Khuvsgul province, and the lowest in Uvs province.