Text: Male factor infertility has been linked with numerous irregularities including sperm number, motility and morphology. It is a known fact that in a range of causes of male infertility, chromosomal aberrations occur in about 2-3 percent of unselected patients with proven subfertility. Among numerous aetiologic factors, chromosomal abnormalities play a primer role in male infertility with abnormal semen parameters. The exact mechanism by which chromosomal anomalies induce infertility is not clear. Studies have indicated that deletions on the long arm of the Y chromosome involving a particular and consistent segment might lead to azoospermia and sometimes to severe oligozoospermia. Several reports on male infertility mention the presence of chromosomal variants or polymorphisms. The Y chromosome has unique characteristics that distinguish it from all other segments of the genome. The major part of the Y chromosome, 60 million base pairs, is transmitted exclusively from fathers to their sons. The proband is a 24 year-old azoospermic Turkish male. He was referred for cytogenetic investigation because of azoospermia. Karyotype analysis of peripheral blood lymphocytes, carried out with standart procedures, revealed a constitutional 46,X,+marY. FISH (fluorescent in situ hybridization) and molecular study will be performed later. This karyotype is associated with a normal phenotype. In this study, we aimed to identify if there is an association between marker Y and azoospermia.