mbiguous genitalia constitute a rare phenotypic presentation of the urogenital system that can signal an underlying life-threatening disorder. The present case relates to a 3 months old infant reared as male child with the mosaic karyotype 45, X/46, X, idic(Y) who presented with ambiguous genitalia. Genital ambiguity was present in the form of partial fusion of labioscrotal folds and microphallus with single opening at the tip of phallus. The child underwent orchidopexy for right inguinal testis at age of 2 months while left testis was present in labioscrotal sac. Basal testosterone level was 160 ng/dl and LH 3 IU/L. Pelvic ultrasonography did not reveal presence of Mullerian structures. Material and method: First Karyotype was performed with peripheral lymphocytes, GTG banded chromosome analysis, the presence and location of SRY gene was investigated using FISH, respectively. Result: Karyotyping confirms the 45, X (monosomy X), while the FISH analysis revealed presence of two cell lines: one cell line with single copy of X chromosome with absence of SRY gene in 70% of cells. Second cell line with one copy of X chromosome and 2 copies of SRY gene in 30 % cell analyzed.