We performed a retrospective study of 17 Turner's syndrome (TS) cases who were diagnosed prenatally in our Genetic Diagnostic Centre, Alsancak-Izmir, Turkey, during the period 2000-2005. The indications for prenatal diagnosis, ultra-sonographic findings and demographic data of the mothers were evaluated from patient records. The most frequent indications for prenatal diagnostic intervention were cystic hygroma (6/17) and hydrops fetalis (4/17). Other indications were advanced maternal age, abnormal triple test [alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (Estriol)] levels in the diagnosis of Down's syndrome and fetal growth retardation. A 45,X non-mosaic karyotype (14/17) was detected in 14 of these cases, while three showed mosaicism with the following karyotypes: 45,XO/46,XX, 45,XO/46,XY and 45,XO/46,X,del (X)(q21;qter), respectively.