['Aneurysm of the internal carotid-posterior communicating artery (ICA-PCoA) is the most frequent cause of sudden unilateral oculomotor palsy. Timely surgery for the aneurysm is the most important factor for third nerve recovery.', 'We scrutinized the world literature with nearly one thousand cases of isolated unilateral oculomotor palsy caused by intracranial aneurysms and treated with surgery. Only those reports (one-third of all) in which the time interval between onset of oculomotor palsy and surgery could be determined were included. We treated 1314 patients with cerebral aneurysms (183 = 14% with ICA-PCoA aneurysms) from our catchment area in Eastern Finland during years 1977-1992. Twenty-eight patients having oculomotor palsy caused by ICA-PCoA aneurysm had surgery as soon as the diagnosis was made.', 'Eight of 9 patients operated within three days (0-3) and 4 of 6 patients operated on within 4 to 6 days the onset of oculomotor palsy had complete recovery of their third nerve function, in contrast to only 4 of 13 patients operated on later. Especially those operated on more than four weeks later had a dismal outcome: only 1 of 6 had complete recovery.'] Does early surgery improve the cure of aneurysm-induced oculomotor palsy?