BACKGROUND: Congenital diaphragmatic hernia (CDH) is a serious condition associated with abnormal development of the diaphragm. Its occurrence among newborns ranges from 1 per 2000 to 1 per 4000. Depending on location, CDH can be divided into four types: diaphragmatic-pleural, parasternal, diaphragmatic-pericardial, and hernias at the esophageal opening of the diaphragm. Hernias can be classified as true or false depending on the presence or absence of the hernia sac. In case of diaphragmatic-pleural hernias, when the intestine, spleen, and stomach almost completely protrude into the pleural cavity, symptoms manifest early in the form of severe cardiorespiratory and gastrointestinal disorders. CLINICAL CASE DESCRIPTION: The article discusses a case of a three-year-old child with a congenital diaphragmatic pleural hernia. From birth, the child experienced difficulty breathing at feeding, coughing; he also had recurrent pneumonia. X-ray examination and computed tomography of the chest revealed a left-sided hernia. Surgery was done via a left-sided thoracotomy, no complications. In four months after the surgery, X-ray examination showed straightened lungs and normal mediastinum; left diaphragm cupula was also normal. The child is considered to be completely healthy due to the absence of symptoms and normal chest X-ray findings. The authors' main goal was to raise awareness among doctors about rare congenital diseases such as CDH. Also, they would like to draw attention to the fact that congenital malformations of the lungs, intestines, and other organs can be unexpectedly manifested at any age. Children with frequent respiratory problems or cardiorespiratory conditions have to be X-rayed as soon as possible to detect congenital malformations of the diaphragm or other chest organs for timely surgical intervention. CONCLUSION: As the authors have noted, in recent years X-ray examination of children often reveals undiagnosed at an early age "findings" related to diaphragm pathology, such as false and true diaphragmatic hernias and dome relaxation. CDH is rare in children older than 3 years and has no specific symptoms. It often leads to delayed diagnostics, often visits to pediatricians because of respiratory infections, retardation in physical development and, as a result, to late surgical treatment.