One hundred medical and surgical patients admitted to an accident and emergency ward were screened for psychiatric disorder. A psychiatric diagnosis was made in 37 patients, 32 of whom were correctly identified by the GHQ. Psychiatric morbidity was associated with being single, lower social class, unemployment, homelessness and living in Bloomsbury Health District or north-east London. It was also associated with not being registered with a GP. The 14 overdose patients were no more likely to receive a psychiatric diagnosis than other patients, yet constituted most of the psychiatric referrals. Few patients were asked by medical staff about emotional worries or problems. A desire to be asked such questions and a past psychiatric history were associated with a psychiatric diagnosis. Routine screening of psychiatric morbidity in both medical and surgical patients and appropriate psychiatric referral of identified patients is recommended. A system of facilitating GP registration is necessary, as much of the morbidity identified could be contained within primary care.