A retrospective analysis of all consecutive helicopter transfers to the Beaumont neurosurgical unit was performed over a two year period from January 1994 to December 1996. There were 55 transfers, 55% of which were for trauma patients. Sixty two per cent were intubated prior to transfer. The mean length of stay at the referring hospital prior to transfer was 12.25 hours (range 3-98 hours). Twenty five per cent underwent a neurosurgical operation within 2 hours of arrival at the unit. Seventy eight per cent of patients either made a full recovery or were left with mild to moderate disability. Whilst helicopters do not seem to result in a marked reduction in total transfer time compared with 'blue light' ambulances, they do result in a shorter time being spent in the unstable transfer environment and this, in turn, might be associated with improved patient outcome.