The incidence and quality of postanaesthetic morbidity in 408 out-patients was examined using univariate and multivariate statistical designs. One hundred and eighty-three patients (44.9 per cent) developed symptoms attributable to the anaesthetic. In 3.9 per cent symptoms persisted for more than 24 hours and 5.4 per cent were unable to follow their normal occupation on the day after the anaesthetic because of the symptoms. The commonest complaint was of drowsiness (30 per cent) followed by headache (13 per cent); 3.9 per cent vomited. Women were more often affected than men; increasing length of operation was significantly associated with both the occurrence and the severity of symptoms. None of the limited number of anaesthetic drugs and techniques used was significantly associated with symptoms. The possible effects on postanaesthetic morbidity of such factors as age, social circumstances, neuroticism, distance travelled to hospital, were also investigated.