This study was set up to investigate whether work as a stoker is associated with an increased risk of specific malignant neoplasms. For this purpose, a cohort of 2777 male stokers was followed up through a 10 year period with regard to cause specific mortality. Comparisons were made with another cohort of unskilled male workers in physically demanding jobs. The mortality of the stokers was significantly increased for lung cancer (standardised mortality ratio (SMR) 145, 95% confidence interval (95% CI) 110-186) and for multiple myeloma (SMR 388, 95% CI 106-994). Also, increases were seen for cancer of the urinary organs and cancer of the mouth and throat. The combustion products to which the stokers have been exposed comprise several carcinogenic agents including polycyclic aromatic hydrocarbons, benzene, arsenic, and radionuclides. It seems likely that the occupational exposure of stokers has contributed to their excess cancer mortality.