Background: In the present paper, the authors describe a case of a rare congenital defect – anomalous origin of the right coronary artery from the main pulmonary artery diagnosed in a 5-week-old infant who was deemed eligible for surgical treatment based solely on echocardiography. Such anatomical abnormalities of the coronary arteries are subtle and thus extremely difficult to visualize, especially in patients in whom permanent extensive damage of the cardiac muscle has not yet occurred. For this reason, the diagnosis is usually established when the disease is highly advanced, oftentimes only postmortem. In this paper, the authors present early echocardiographic evaluation, successful surgical treatment and post-operative echocardiographic examination. Case presentation: Fetal echocardiographic examinations demonstrated single vascular anomalies. The suspicion was verified after birth. Other congenital defects, including genetic defects, were also investigated. In the 5th week of life, cardiac ECHO showed abnormal origin of the right coronary artery from the trunk of the pulmonary artery. The child was deemed eligible for surgical treatment of the defect. The surgical translocation of the ostium of the right coronary artery to the aorta was done with success, and the child was discharged on the 14th day of hospitalization. Conclusion: The present case report demonstrates that careful examination of the child with precise echocardiographic examination makes it possible to establish an early diagnosis of this rare defect. This discrete defect can be treated early, before the symptoms, often connected with irreversible changes in the myocardium, appear.