Objective: Myelodysplastic syndromes (MDS) are a heterogeneous group of malignant clonal hematopoietic stem cell disorders characterized by bone marrow failure, ineffective hematopoiesis, peripheral blood cytopenias, atypic cytological profile, increased apoptosis, and increased likelihood of evolution to acute myeloid leukemia (AML). Cytogenetic findings are major determinants in the diagnosis, classification, pathogenesis, prognosis, and treatment in patients with MDS. Cytogenetic analysis is a mandatory step in the full evaluation of a newly diagnosed patient. The aim of the present study was to retrospectively evaluate the cytogenetic findings of 221 MDS patients in Istanbul University Cerrahpasa Medical Faculty, Medical Biology and Genetics Department. Material and Methods: Cytogenetic analyses of 221 patients (89 female, 132 male) were performed on bone marrow cells using a trypsin-Giemsa banding technique. Metaphase cells were obtained from short-term unstimulated cultures. When possible, at least 20 metaphases were analyzed and 10 of them were fully karyotyped. Results: Among the 221 patients, 122 had no karyotype anomalies (55.20%) and 99 (44.80%) had clonal cytogenetic abnormalities; with 46 (20.81%) having one, 19 (8.59%) having two and 34 (15.38%) having complex (>= 3) abnormalities. According to the International Prognostic Scoring System (IPSS) cytogenetic categories, 130 (58.82%) patients presented with a good karyotype, 54 (24.44%) patients with intermediate karyotype and 37(16.74%) patients with poor karyotype. Conclusion: Although some cases appear to have a normal karyotype, the technical failures such as inability to obtain sufficient analyzable metaphases may reduce the actual proportion of abnormal cases. The examination of 20 or more metaphases could further increase the sensitivity of cytogenetic analyses with clinical impact in individual cases by identifying additional abnormal clones or subclones.