Background Aim of study was to evaluate the prevalence and etiological factors that contribute in midline diastema in Kurdistan region-Iraq population among different age groups and genders. Material and Methods Orthodontic patients sample of (EX: 1021orthodontic patients (537 males and 484 females) were randomly selected from Kurdistan-region population, attending to orthodontic department of khanzad polyclinic teaching center (General directorate of hawler / Ministry of health/ Kurdistan region- Iraq) during 2018-2019 period. Aged (13-35 years) with mean age ± SD was 19.6 ± 4.8 years, with a median of 19 years. The examination included patient history taking, intraoral examination, photograph, intraoral periapical radiography of incisors area and panoramic radiographic. Diastema consider positive when the space between central incisors is 0.5mm and more, width was measured clinically used digital Vernier calipers at one millimeter above the incisors edge. Results The prevalence of midline diastema was 23.2%. located in the maxilla (97%), in mandible (1.3%) and in both was (1.7%). The prevalence of midline diastema differs significantly between the age groups ( p < 0.001). The highest prevalence (55.8%) was among patients aged ≥ 30 years, and it was also high (37.7%) among those aged < 15 years. The prevalence among females (26.4%) was significantly higher than the prevalence (20.3%) among males ( P = 0.020). The main causes of midline diastema in females was thumb sucking and missing lateral incisors (14.1% and 12.5% respectively) and in males was high labial frenum and super numerally teeth (39.4% and 30.3% respectively). Conclusions Prevalence of diastema in Kurdistan regional- Iraq area was (23.2%), the location mostly in maxilla (97%). The prevalence of diastema in females more than males. The main causes of diastema in females was thumb sucking and missing lateral incisors while in the males was high labial frenum and super numerally teeth. Key words: Prevalence, midline diastema, high labial frenum, thumb sucking.