The purpose of this review is to asses the current knowledge of mucopolysaccharidosis (MPS), with reference to the serious complications which may arise in connection with anaesthesia and operation. MPS consists of a heterogeneous group of hereditary diseases which are characterized by an abnormal accumulation of mucopolysaccharides, especially in cartilaginous and bone tissue. Because of their progressive and disabling nature, frequent surgical intervention is common, and is associated with a high degree of per- and postoperative risk. The clinical manifestations of MPS are frequently dwarfism, scaphocephaly, grotesque facial features with snub nose, hypertelorism, macroglossia and dental anomalies. The chest is deformed by pectus carinatum or excavatum, club-formed ribs and kyphosis with gibbus. Furthermore, cardiomegaly, abdomen pendens, hepatosplenomegaly, umbilical hernia, corneal clouding, conductive deafness and subnormal intelligence are common findings. Prior to operation, patients should be thoroughly evaluated through clinical examination and laboratory investigations. In particular, lung function should be optimized by lung physiotherapy and treatment of airway infections. When inducing general anaesthesia, spontaneous respiration is recommended until the patient has been intubated, as airway anomalies, bleeding and salivation may make intubation extremely difficult. Local or regional anaesthesia is often preferable, though age and mental status are relative contraindications. When used in combination with careful sedation, many problems may be overcome. Postoperatively, it is important to treat stagnation of secretions and airway infections with lung physiotherapy positive end-expiratory pressure, and antibiotics. In connection with anesthesia, it is vital to monitor the patient carefully before, during and after anaesthesia.