Patients with hypohidrotic ectodermal dysplasia (HED) are characterized by the clinical manifestations of hypodontia, hypohidrosis, hypotrichosis and a highly characteristic facial physiognomy.This disorder is inherited as an X- linked trait. This report presents three cases with HED in which the clinical evalua-tion (intraoral and radiological), genetic findings and SEM examination of hair. Boys 6 to 14 year old and a 11 year old girl were referred to the Marmara University, Faculty of Dentistry, complaining of oligodontia in the maxillary and mandibular arches and delay in eruption of other teeth. Peg-shaped teeth have been observed. The dermatoglyphs of the patients were striking. SEM exmimation of hair demostrated a distinctly abnormal longitudinal groving along the entire length of each hair and a desqua-mation of the surface cuticles. The treatment was planned in a multidisciplinary odontological group involving pediatric dentistry, orthodontics, prosthodontics and oral surgery and maxillofacial radiology of future dental habilitation. A specially designed overdenture, a removable prosthesis and osseointe-grated implants were constructed. Periodic recall visits were advised, to monitor the dentures and implants during periods of growth and development, and eruption of the permanent teeth.