in order to evaluate the frequency of peroperative anaphylactic reactions in children. Data were collected from 38 Belgian and French institutions. During the study period, 162 551 children were anaesthetized, and 21 anaphylactic reactions were observed. Sixteen reactions were due to exposure to natural rubber, four were drug-related (vecuronium, suxamethonium, contrast medium and penicillin) and one occurred during removal of a hydatid cyst. The overall incidence (1/7741 anaesthetics) was close to that reported in adults (1/6000 to 1/6500), but anaphylaxis to latex was the main cause of anaphylactic reactions in children while it accounted for only 10% of reactions in adults. The incidence of reactions to muscle relaxants, the main aetiology reported in adults, appears to be ten times less frequent in children (1/81 275 anaesthetics) compared with adults (1/8000). A11 children were successfully resuscitated. Risk factors, clinical signs and treatment are described.