The loss of an X chromosome results in short stature and often in primary ovarian failure, but the effect of extra X chromosomes is less clear, especially in 48,XXXX women. We report a girl with a 48,XXXX karyotype with tall stature (181.8 cm), primary ovarian failure and low DHEAS levels. A review of the literature shows that, apart from an intellectual deficit, the phenotype is very heterogeneous. The few data that are available in the literature indicate that tall stature and primary ovarian failure are not essential characteristics of the 48,XXXX phenotype.