Infants with one testicle in the abdominal cavity are cryptorchidism caused by an abnormal testicular descent, which can be treated with waiting, medication or surgery. The testicle initially originates in the posterior abdominal wall and descends through the inguinal canal into the scrotum as the fetus develops. Cryptorchidism occurs when there is an obstruction to the descent process and the testicle becomes lodged in the abdominal cavity, inguinal canal, or at the entrance to the scrotum. The possibility of the testicle descending on its own is still present up to the age of 1 year, so it is possible to watch and wait up to the age of 1 year. After 0.5 years of age, when the testicles have not yet descended into the scrotum, chorionic gonadotropin can be used for a short period of time. If medication is not effective at 1 year of age, surgical treatment such as testicular descent fixation is needed to avoid the risk of infertility or malignancy associated with cryptorchidism. Parents of infants are advised to closely observe the descending testicles of their infants and follow the medical advice for observation or medication or surgical treatment, and medication should also be used under the guidance of a physician.