In a cross-sectional study of midline diastemas in a South Indian (Madras) population, 9,774 patients aged 13-35 years were screened. True midline diastema was defined as one without periodontal/periapical involvement and with the presence of all anterior teeth in the arch. Sample purification resulted in a research sample of 166 patients with true midline diastemas. The incidence of true maxillary midline diastema (160/9774-1.6%) was greater than that of true mandibular midline diastemas (31/9774-0.3%). No direct etiologic factor for the midline diastemas was noted. Spacing in the anterior region was the most significant factor associated with the midline diastema.