Hypophosphatasia (HP)is a rare inherited disorder characterized by defective bone and teeth mineralization, deficiency of serum and bone alkaline phosphatase (AP)activity. The diagnosis is based on serum alkaline phosphatase essay and molecular analysis of the tissue non specific alkaline phosphatase (ALPL) gene. AP participates in tooth formation and is seen in dental and peridental cells. They are mainly seen in the following forms: infantile, childhood, adult and odontoHP. The dental clinical signs consist in mobility of teeth, premature and spontaneous loss of primary and/or permanent teeth without inflammation of the gums, and sometimes in localized enamel hypoplasia. In the milder forms, rarely diagnosed per se, premature exfoliation of teeth is a trigger sign which can leed to a possible diagnosis. In infantile and childhood hypophosphatasia, the anterior primary teeth are generally lost spontaneously before 3 years of age. In the adult forms, the medical history could elicit a memory of early loss of teeth in childhood. Dental management consists in early diagnosis, prevention and prosthodontics.