Three phenotypic female sisters in a sibship of four sisters and one brother were found to have pure ovarian dysgenesis, which was confirmed by the finding of streak gonads at laparotomy in two of the three sisters who presented with amenorrhea and lack of secondary sexual characteristics. No evidence of any other congenital anomaly was found in any of these sisters. Pure gonadal dysgenesis syndrome distinguishes a group of women with primary gonadal failure with amenorrhea whose heights are over 152 cm and who are without either webbed necks or any of the other somatic anomalies that are characteristic of Turner's syndrome. Cytogenetic studies revealed a normal female (46,XX) karyotype in all the affected members. Endocrine studies indicated that the affected sisters had elevated FSH and LH values with decreased plasma estradiol and urinary estrogen determinations. This is the second report of a family with 46,XX karyotype that meets all the criteria for the pure gonadal dysgenesis syndrome. The multiple affected sibs suggests an autosomal recessive mode of inheritance.