Introduction: Turner syndrome (TS), in which there is loss of all or part of one sex chromosome, occurs in one in 2500 live-born females and is associated with characteristic clinical and physiologic abnormalities -short stature and gonadal failure.. Gonadal function is also clinically important, ranging from the onset of spontaneous puberty and the potential for fertility to complete gonadal failure. Klinefelter syndrome (KS) affects males carrying an additional X chromosome, which results in male hypogonadism, androgen deficiency, and impaired spermatogenesis. Some patients may exhibit all of the classic signs of this disorder, including gynecomastia, small testes, sparse body hair, tallness and infertility. Purpose and objectives: To evidentiate the groth hormone treatment effect in increasing height in TS and the testosterone replacement therapy effect in virilisation in KS. Materials and methods: Our study includes 5 cases diagnosed with Turner syndrome and 3 cases with Klinefelter syndrome between 2005-2011 in Iasi Medical Genetics Center in order to illustrate some variants and to show the cytogenetic complexity of these syndromes which reflects in the clinically diverse presentations. Cytogenetic diagnosis was performed using peripheral lymphocytes with G banding and Fish analysis. Results and discussion: Of the 5 cases that had been diagnosed with Turner Syndrome, all of them had various skeletal malformations raging from the shortening of the fourth metacarpal to dental abnormalities, face malformations and hypostature while the karyotypes were slightly different between the 5 cases analyzed. Furthermore, one case (karyotype 45,X/46,X,r(X)(p22.1q24)[24]/[23]) had a congenital unilateral ovary which added to the complexity of the clinical approach. We also found one case (karyotype 46, XX/45,X[41][7]) that had the characteristic sausage-like appearance of the toes. Of the 3 cases diagnosed with Klinefelter syndrome, 2 cases had distinctive intellectual and learning disabilities (karyotypes 48,XXY[96]/[3] and 48,XXYY/47,XYY), while in the other case (karyotype47,XXY(38)) hypogonadism, which led to gynecomastia and late puberty, which in turn stood as the basis for psychosocial problems, represented the main features. Conclusion: Our study shows the cytogenetic complexity of Turner and Klinefelter syndromes which is reflected on the clinical features of the patients outlining the importance of karyotyping in these plurimalformative syndromes.