Objective: The main aims of this study were to determine the prevalence of Midline Maxillary diastema according to three common races (Tajik, Pashtoon, and Hazara), sex, and type of dental arch among 999 OPD patients in National and Specialized Stomatology Hospital, Kabul-Afghanistan. Materials and Methods: 999 patients in 15-30 years were selected by a systematic random sampling method during the seventh month. Patients were examined directly intra-orally, and information was collected by a single researcher, recorded on pre-prepared questioner forms, and then data analyzed by the SPSS. 25 software.