Ectodermal dysplasia is a heterogeneous condition characterized by affected ectodermal structures, among which the teeth and skin with its derivatives (hair sweat glands) are the most frequent. The aim of this work is to present the analysis of dental traits in five families (affected boys and their mothers) with hypohidrotic ectodermal dysplasia (HED), and to evaluate the importance of orofacial and dental findings in the determination of female HED gene carriers. Hypodontia (oligodontia) was found in all the patients. The mothers, gene carriers, had either hypodontia or a reduced size of teeth with a particular morphological, peg shape. In patients with hypohidrotic ectodermal dysplasia the deciduous second molar teeth were mostly affected by taurodontism. The characteristic dental finding in heterozygous females of the mandibular peg shaped incisors and canines, as well as of hypodontia or peg shaped upper lateral incisors can be used as a reliable criterion for the detection of HED gene carriers.