Concern has been expressed recently about apparent increases in the incidence of leukaemia amongst young people living in certain geographical areas. We analysed the incidence of childhood leukaemia in South-East Scotland (excluding North-East Fife) from 1970 to 1984. There was a significant geographical variation in incidence of ALL with an excess in Fife concentrated in a small area of one district partly balanced by a relative decrease in Edinburgh. We feel that the variation is unlikely to be an artefact of geographically biased mis-diagnosis.