In 1964, one of us (WHG) undertook a retrospective study of bacterial meningitis in childhood in the north east of Scotland during the period 1946-61. We have recently carried out a similar review of cases occurring during 1971-86, to compare the incidence, mortality, and bacteriological patterns. During the earlier period 285 cases occurred, a total incidence of 16.9/100,000 children per year. In the later period 274 children were affected, an annual incidence of 17.8/100,000. The overall mortality rate fell dramatically from 11.9% to 1.8%, the latter figure comparing favourably with recent published studies from Scandinavia and the United States. There was a change in the bacteriological profile in the second period with a significant rise in cases due to Haemophilus influenzae at all ages. A fall in cases of meningococcal meningitis was significant in infants under 1 year of age only. Possible reasons for the change in the bacteriological pattern are discussed.