Histopathological diagnoses were compiled for 100 sinonasal cancers and 259 lung cancers in nickel refinery workers, including cases from Wales, Canada, and Norway. The sinonasal cancers comprised squamous cell carcinomas (48 percent), anaplastic and undifferentiated carcinomas (39 percent), adenocarcinomas (6 percent), transitional cell carcinomas (3 percent), and other malignant tumors (4 percent). The lung tumors comprised squamous cell carcinomas (67 percent), anaplastic, small cell, and oat cell carcinomas (15 percent), adenocarcinomas (8 percent), large cell carcinomas (3 percent), other malignant tumors (1 percent), and cancers not otherwise specified (6 percent). Possible selection bias in these data cannot be excluded, since the histological diagnoses represent 63 percent, 68 percent, and 100 percent of cases of sinonasal cancer and 24 percent, 47 percent, and 86 percent of cases of lung cancer in the Welsh, Canadian, and Norwegian workers. This study suggests that (a) the sinonasal cancers in nickel refinery workers conformed to the usual distribution of histological types observed in the general population (in contrast to the predilection for adenocarcinomas in wood workers), and (b) the lung cancers in nickel-refinery workers showed preponderance of squamous cell carcinomas and deficit of adenocarcinomas, compared to prevalent proportions of these neoplasms, possibly reflecting the paucity of women in the cohorts and temporal trends during the six decades in which the tumors were diagnosed.