A total of 1,388 workers employed for at least 3 months at a copper/nickel smelter and nickel refinery were followed up for cancer from 1953 to 1987 through the Finnish Cancer Registry. There were 1,339 male and 49 female workers, making a total of 27,130 and 706 person-years, respectively. All of the women worked in the refinery, which opened in 1960, the same year the smelting of nickel began. A total of 67 cancers were diagnosed among the men, the standardized incidence ratio for all cancers being 1.0. No cancer was found among the women (1.8 expected). The risk of cancer among men was analysed according to primary site, exposure to nickel, type of work, years since first exposure and age at diagnosis. In the subcohort of nickel refinery workers, one case of sinonasal cancer was observed, against 0.02 expected, but otherwise no significantly increased risks of cancer were found. In addition to the small size of the cohort, the non-positive finding concerning lung cancer might be related to the relatively low arsenic exposure and, perhaps, to the late commencement of nickel production.