Introduction. In 1963 Beckwith presented a report on the first patient with extreme cytomegaly of adrenal cortex, hyperplasia of kidneys and pancreas and Leydig cell hyperplasia. Wiedemann completed description of the new syndrome by adding umbilical hernia and macroglossia. The diagnosis is made based on the clinical signs of omphalocele or some other umbilical deformity, macroglossia, congenital asymmetry, visceromegaly (liver, pancreas, and kidneys). Case Outline. A 16-month-old male child was admitted for examination because of macroglossia. He underwent examination on several occasions by an endocrinologist due to recurrent hypoglycaemic crisis. The patient was observed by a paediatric neurophysicatrist for disorders of mental development. Hypoglycaemia, muscular hypotonia of the anterior abdominal wall with umbilical hernia and macroglossia were observed by clinical examination. Inratraoral examination revealed macroglossia with microstomia, suckling and swallowing difficulties, hypotonia of the perioral muscles with increased salivation. It was therefore decided to perform surgical reduction of the prominent tongue and develop good condition for nutrition, speech function and the development of orofacial system. Conclusion. The diagnosis of macroglossia is based on subjective clinical criteria such as the morphology and amount of protrusion of the tongue, difficulty in articulating sounds, breathing, and hypersalivation. Some authors have suggested that the tongue size may be analyzed radiographically with a cephalogram. Treatment of macroglossia is controversial because of the absence of objective clinical criteria.