A 46, XX male karyotype was detected in 36-year-old male who has normal external genitalia and azoospermia. The patient was married 3 years ago and considered to be primary hypogonadism on the level of endocrine function tests. He had markedly elevated scrum FSH (42 ㎖U/㎖), elevated serum LH (18 m IU/nl) and decreased serum testosterone (1.9 ng/㎖). The volume of testes was small of 8 ㎖. Most 46,XX males are attributable to an interchange of the pseudoautosomal region which contains the sex-determining region of the Y chromosome (SRY) gene with the X chromosome. XY dual probe fluorescence in situ hybridization (FISH) was performed and two X chromosome centromere signals were detected but Y chromosome heterochromatin signal was not shown. The polymerase chain reaction (PCR) was used to amplify a single-copy Y-specific sequences in SRY gene and DYS14 loci which are expressed in testicular tissue. All the PCR products were positive for DYS14 and SRY sequences. In this study we will discuss the genes which are related to sex determining and spermatogenesis on Y chromosome.