ABSTRACT
Leydig cell tumor is a rare form of testicular neoplasm which comprises 1-3% of all testicular tumors and only about 3% of these tumors are bilateral. A few Leydig all tumor have been described in patients with klinefelter's syndrome so far.: The patient described in this case report was a 24 year-old man with chief complaint of infertility for one year. Physical examination, semen analysis, testes sonography and hormonal assay were done for him. Right side simple orchiectomy was performed for patient. This tumor is always benign in children and approximately 90% are benign in adults. Clinical presentation is testicular enlargement, gynecomastia, sexual activity disturbances such as decreased libido, infertility and azoospermia. We recommend complete exam and karyotype in patients with infertility and azoospermia