Differential and spatial analyses of respiratory system cancer were undertaken for New South Wales and Sydney for the period 1980-1986. The source of data was death certificate information on the unit list mortality file tapes provided by the Australian Bureau of Statistics. Characteristics of persons dying included age, sex, birthplace, occupational status and cause of death (ICD9 classification). The aim was to identify populations at risk from respiratory system cancer, and where they were located. Deaths were disaggregated for the abovementioned categories by cross-tabulation at the state level and for geographical areas having populations with higher levels of respiratory cancer mortality. Never-married males of lower occupational status had higher rates of respiratory cancer, mainly lung cancer. Divorced men also had higher mortality as did widowers who were in lower occupational status work, while married men in managerial work also had significantly high mortality. The marital status variation was mostly not found with females, although significantly high female mortality was found in several low socioeconomic status areas of Sydney. Mortality of both sexes was significantly higher in metropolitan Sydney than in the rest of New South Wales and associations between older age mortality and some industrial areas were found in Sydney.