The study of the postcranial skeleton of 68 specimens of four genera in the family Agamidae helped revealing 11 sexual characters which are present in all mature specimens. The analysis of sexual variation shows a relatively high stability of these features at the level of this family. Comparison of the age variation in the sexual dimorphism shows that secondary sexual characters are formed more intensively after a specimen has reached the reproductive age. In old specimens the sexual differences are smothened.