South Australian Cancer Registry data for 1977-1986 have been used to compare the incidence of cancer for overseas-born populations and for the State as a whole. British and Irish migrants were found to have a higher incidence of all cancer sites combined, largely because of elevations in the incidence of cancers of the lung, stomach and female breast, whereas southern-European migrants showed a lower incidence of cancer, mostly as a result of low incidence rates for cancers of the colon, prostate, lung (women only), melanoma and female breast. Differences in incidence also were evident by country of birth for cancers of the buccal cavity, oropharynx, nasopharynx, oesophagus, liver, larynx, pleura, testes, uterine body, bladder and kidney, and various lymphohaematopoietic cancers. The aetiological implications of these findings, particularly in relation to environmental and life-style factors, are considered.