Patients are normally thought to have recovered from general anaesthesia within a few hours after day-case surgery. Previous recovery studies using objective psychometric tests showed a return to baseline values within this period. Nevertheless, patients are advised about what activities they should not undertake in the subsequent 24 h because it is feared that the residual anaesthetic effects may impair their ability. These studies did not follow patients out of hospital and their relevance to the real world is not known. Using the cognitive failures questionnaire, a standard measure of performance of everyday tasks, 54 patients were asked to report their own performance after general anaesthesia for the 3 days after discharge from hospital: 30 local anaesthetic patients were studied for comparison. The general anaesthesia group reported a highly significant greater incidence of cognitive failures after anaesthesia compared with the local anaesthesia group. This suggests that the residual effects of anaesthesia persist beyond 24 h.