Five cases of awareness have been identified during total i.v. anaesthesia with mechanically controlled ventilation and neuromuscular block. Two of the cases resulted from inability to deliver the target dose of anaesthetics, while the patient's need for anaesthetics was greater than anticipated in three. It is concluded that all cases were caused primarily by lack of experience, and could have been prevented. These five cases occurred in experience from approximately 2500 patients anaesthetized with this technique. Pre-, per- and postoperative data on the most recent 1727 patients have been entered into a database and may serve to provide data on the group of patients in whom the five cases of awareness occurred. (Br. J. Anaesth. 1993; 71: 782–787)