Objective: To identify the distribution of cytogenetic abnormalities among Turkish women with premature ovarian failure (POF). Method: A karyotype analysis was performed at the Medical Genetics Department of Zekai Tahir Burak Women's Hospital, Ankara, Turkey, for 75 women younger than 40 years found to have POF over a 5-year period. Results: There were 18 familial cases (24%), 1 of which involving an abnormality of the X chromosome [46,X,del(X)(q22)]. Sixteen patients (21.3%) had chromosomal abnormalities such as Xq and Xp deletions, translocations, and numerical aberrations; 2 had Swyer syndrome; 2 were fragile X premutation carriers; and 1 had galactosemia. Conclusion: A genetic cause of POF was identified in 39 (52%) of 75 patients. A thorough genetic evaluation of women with POF should be performed regardless of clinical features suggestive of chromosomal abnormality. © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.