This study reviewed cytogenetic analysis in amniotic fluid cells and detected chromosomal abnormalities according to patient`s indications, The 511 cases obtained by amniocentesis were performed using traditional cytogenetic methods at the Institute of Reproductive Medicine and Population, Seoul National University between January and December 2009. The cytogenetic results of 511 cases on cultured amniotic fluid samples showed normal chromosomes (94.9%), chromosome heteromorphisms (2.7%), and chromosomal abnormalities (2.4%). Total 12 cases of abnormal fetal karyotypes were identified including 10 cases (2.0%) of numerical aberrations, 1 case of structural aberration, and 1 case of mosaicism. Numerical abnormalities consisted of autosomal aneuploidies with trisomy 18 (1 case) and 21 (8 cases) and sex chromosome abnormality (1 case). One case of structural abnormality showed balanced reciprocal translocation which was inherited from maternal carrier. The rate of indication with chromosome aberrations was most frequently detected in advanced maternal age, followed by abnormal maternal serum marker positive and abnormal ultrasonographic findings. Among fetuses with an abnormal karyotype, the advanced maternal age could be considered as a predictive marker. These data provide a comprehensive review of the prenatal diagnosis and helpful information in genetic counseling for patients with the high-risk pregnancy.