Beckwith-Wiedemann syndrome (BWS) is an overgrowrth syndrome characterized with omphalocele, macroglossia and hypoglycemia in the newborn. Here in we present a sister and a brother with a history and clinical findings suggesting BWS; the sister presented with amenorrhea at the age of 16 years. Case 1: A 16-year old girl, who had been evaluated by a gynaecologist for primary amenorrhea, was admitted to the Clinical Genetics of our hospital because of "macroglossia" and prognathism, suggesting a "genetic syndrome". She was also complaining of difficulty in chewing due to dental problems. Her history was remarkable for omphalocele during the neonatal period which had been corrected surgically. Her tongue, which was even more larger, had regressed during the following years. Her brother had also a "large" tongue in addition to cryptorchidism which was corrected surgically. On physical examination, the height was 173 cm (over the 97th. percantil) and the weight was 61.5 kg. Prognathism and lineer indentations on the ear lobes were noted. On laboratory studeies, a routine biochemistry, in addition to FSH, LH, estradiol, and progesteron levels were in the normal limits. The karyotype was 46, XX. Neither the uterus, nor the ovaries could be visualized on pelvic ultrasonography. A n abdominopelvic magnetic resonance imaging showed a uterus in infantile dimensions and considerably enlarged ovaries located bilaterally in paracolic region and in a normal than higher position. Case 2: The brother of the index case, then 14 years old, was free of any complaints. However, he had also a history of macroglossia, cryptorchidism and omphalocele. Physical examination was unremarkable other than an enlarged tongue, lineer indentations on ear lobes and pits on the aericulae. Discussion: The two siblings were diagnosed with Beckwith-Wiedemann syndrome based on the typical history (macroglossia and omphalocele) and physical examination (enlarged tongue, indentations on ear lobes and pits on the auriculae). The BWS is a sporadic disorder most of the time and familial occurance is rare. It is noteworthy that the parents of the index case are apparently normal. In the index case, now 20 years old, menarche has not occured since the initial evaluation. To our knowledge, primary amenorrhea and unusually high located ovaries have not been reported in BWS before.