Cryptorchidism is the unilateral or bilateral absence of a testicle in the scrotum. The condition is much more common in premature babies (up to about 30%), and can also be seen in full-term boys, but at a lower frequency (up to 4%). Usually the testicle is positioned in the scrotum during the first 6 months spontaneously. If it continues to be missing after that, clarification and subsequent treatment is required. It is possible that the problem will be noticed by the mother while using the toilet. The diagnosis is made by a doctor. The general practitioner should specify and track the problem over time. Usually the testicle is retained in the inguinal canal. The skin of the scrotum appears smooth and underdeveloped (on the present side). Cryptorchidism can be both unilateral and bilateral. The undescended testis can also be found in ectopic places, under the skin in the perineum, or completely absent. In case of suspicion of agenesis (complete absence of testicles), additional hormonal tests are carried out. How is the diagnosis made? First of all, it is recommended to see a specialist. Inspection and palpation are performed. Clarification continues with imaging studies – ultrasound examination, computer tomography. If genital abnormalities are suspected, the function of the adrenal glands is determined. The condition may be part of the dysmorphic features of an underlying syndrome, necessitating a comprehensive evaluation of all organs and systems and a targeted search for other accompanying abnormalities. Cryptorchidism should be carefully differentiated from the so-called “elevator testes” (retractable). In the second year, a pronounced cremasteric reflex is observed, which is activated during excitement and brings particularly unpleasant sensations (cold, pain). Due to the contraction of the cremaster muscle, the testicle is pulled up into the inguinal canal. It may give the false impression of a missing testicle in the scrotum. Careful examination and follow-up in 3 to 6 months is required. What is the behavior when diagnosed? Once the problem with a testicle located in the inguinal canal is specified, spontaneous descent is expected within the first year. Delay after 1 year of age is associated with loss of germ cells and subsequently results in sterility. Uncorrected cryptorchidism carries the risk of malignant transformation of the retained testis. The definitive treatment is operative – it is called orchidopexy. Timely implementation is important to avoid negative long-term effects. References: 1.Nelson Textbook of Pediatrics Elsevier eBook on VitalSource, 20th Edition by Robert M. Kliegman, MD, Bonita F. Stanton, MD, Joseph St. Geme, MD and Nina F Schor, MD, PhD; 2. Differential diagnosis of childhood diseases, ed. Arso, ed. Prof. N. Mumdzhiev