Spermatogenesis, hormonal regulation of male reproductive functions and performance of the male sexual act are the three main groups of male reproductive functions that are possible due to the integrity of anatomical structures and the uniformity of physiological processes in the body. Infertility is defined as the inability to conceive after one year of unprotected intercourse. It globally affects between 8% and 12% of couples, of which the male factor is responsible for a third of cases. Fertility disorder manifests itself at three basic levels: pretesticular, testicular and posttesticular. Pretesticular causes of infertility are endocrinological where there is a disorder of the hypothalamic-pituitary axis with a reduced production of testosterone or sperm. Testicular causes are associated with pathological changes in the testis (chromosomal disorders, cryptorchidism, varicocele). Posttesticular causes include all conditions that interfere with the drainage of sperm from the site of production to the urethra. The majority of the evaluation of male infertility is based on a well-taken medical history and physical examination. Other tests are analysis of semen and hormonal status, and if necessary additional diagnostic tests are performed (chromosomal testing, postcoital test, testicular biopsy), all with the aim of finding reversible causes of infertility that can be successfully treated. The therapeutic approach can be non-surgical and surgical, and nowadays assisted reproductive technology is becoming increasingly important as a treatment modality. If these methods are not proven successful, child adoption should also be considered. Patients should also be provided with psychological assistance, if needed.