There have been few studies primarily concerned with the relative frequencies, aetiologies and prognoses of ocular motor palsies. Those published have emanated largely from neurological tertiary referral centres rather than primary ophthalmology departments. We have performed a retrospective study of all patients with acquired III, IV or VI cranial nerve palsy who were seen in the orthoptic department at Ninewells Hospital, Dundee, over the 9 year period from 1984 to 1992. A total of 165 cases were identified. VI nerve palsies accounted for the majority of patients (57%), with IV nerve palsies (21%) occurring more frequently than III nerve palsies (17%) and multiple palsies (5%). Thirty-five per cent of cases were of unknown aetiology and 32% of vascular aetiology. The incidence of sinister pathology-neoplasia (2%) and aneurysm (1%)-was surprisingly low. Fifty-seven per cent of all patients made a total recovery (in a median time of 3 months) and 80% made at least a partial recovery. The results are contrasted with those of previous studies and the value of associated symptoms and of further investigation in the assessment of these patients is discussed.