Eighty-seven cases of cardiac arrest from the first 2000 incidents reported to the Australian Incident Monitoring Study were reviewed. "Cardiac arrest" was taken to include patients who were either pulseless or had electrocardiographic asystole or ventricular fibrillation. Cases were grouped by primary cause--drug administration (19), vagal stimulation (16), hypoventilation (15), bleeding (13), anaphylaxis (6), direct cardiac stimulation (4) and miscellaneous (14). Overall, 20 patients died (23% of the 87 cases); all of these were in the hypoventilation, bleeding, or miscellaneous groups (4, 9 and 7 patients, respectively). Cardiac compression was performed in 66% of patients; 20% were defibrillated; adrenaline was given to 42% and bicarbonate to 3%. There was a clear anaesthetic cause for 46% of this series of arrests, and with hindsight, a preventable factor was present in over half (58%) of these. Preventative strategies regarding staffing, equipment, policy and procedures are suggested.