Infantile hemangiomatosis is among the most common vascular tumours of childhood that is generally accepted as benign. Some cases may have multiple hemangiomas with organ involvement, especially of the liver. This case report will present the clinical and laboratory findings obtained during the treatment and follow-up of a 36-day-old female baby with hemangiomatosis with diffuse liver involvement, high-output heart failure, and pulmonary hypertension.