Aim: The purpose of this study was to evaluate the prevalence of mid line diastema between the group of Iraqi students of Dentistry College in Baghdad University, and to determine the etiological factors of this diastema whether it is due to height frenal attachment or due to the discrepancy in the width of the anterior teeth as etiological factors or/and another cause and to determine the gender difference. Materials and methods: Out of 600 students aged between 18-23 years were clinically examined; only 41 students (30 females and 11 males) fulfilled the inclusion criteria and were having diastema. Maxillary median diastema and mesiodistal width of the sex upper anterior teeth was measured directly (intra orally) with stainless steel vernier calipers. Results: Results showed that about 30 females and 11 males were only having maxillary midline diastema from the total sample. There was no significant difference between males and females concerning the width of maxillary middiastem. In both sexes, the mesiodistal width of all anterior teeth was nearly equal except the maxillary left lateral incisors which were significantly wider in females than in males. Conclusion: In dentally aware societies the presence of diastema was un-aesthetic so many students improved such appearance by orthodontic treatment or restorative veneer, therefore Iraqi students had less prevalence of maxillary diastema than other studies. Females express more prevalence of maxillary midline diastema than male. Mesiodistal width of upper anterior teeth is nearly within the normal range of Iraqi norms. Another etiological factor such as hereditary, genetic or oral habit can be considered as a cause of diastema in our sample who have diastema without high frenal attachment or tooth width discrepancy.