Craniosynostosis occurs in one out of 2,000 births. It results in primary skull deformations requiring surgical repair, in infants with a body weight of less than 10 kg. Pure craniosynostosis is the most frequent situation, where the risk for cerebral compression during brain development is the lowest. Therefore the aim of surgical correction in this case is mainly cosmetic. Conversely, in syndromic craniosynostosis, associated malformations are more common and cerebral, visual and respiratory consequences of complex facio-craniosynostosis are usually severe. Current surgical techniques consist of a total skull vault reconstruction which carry a high risk of sudden and major blood losses. Intraoperatively, whatever the type of craniosynostosis, mean blood losses corresponding to 90% of estimated red cell mass have to be anticipated. These blood losses vary according to the type of skull deformation and the type of surgery. Accurate evaluation is usually difficult and must be based more on calculation of red cell mass variations than on simple monitoring of surgical drainage. Invasive haemodynamic monitoring is always required. To reduce the amount of homologous blood transfusion, peroperative haemodilution seems to be the most suitable technique, due to unresolved technical difficulties in autotransfusion practice in infants. Severe facial deformities are associated with chronic hypoxaemia and cerebral compression representing major risk for these children in poor condition undergoing such major surgical procedures. With experienced teams, this high-risk surgery carries a low peroperative mortality (less than 1%) and morbidity rate. The latter includes essentially transient peroperative hypotension. The excellent final cosmetic and functional results justify the practice of this surgery in children with a bodyweight of less than 10 kg.