Routine statistics of occupational mortality and incidence of cancer have consistently shown high rates of lung cancer in butchers. Possible explanations include infection by carcinogenic papilloma viruses, exposure to polycyclic aromatic hydrocarbons and nitrites in the preservation of meat, or a confounding effect of tobacco. To explore these possibilities, we have examined the mortality of 1610 men employed at three British companies processing pork, beef, lamb, bacon, and other meat products. The overall death rate was less than in the national population (271 deaths observed, 310 expected) but there was an excess of deaths from cancer (87 observed, 80 expected), and in particular from lung cancer (42 observed, 32 expected). The risk of lung cancer was concentrated in subjects exposed to recently slaughtered meat, especially after an interval of 10 or more years. These findings increase suspicions of a risk of lung cancer in butchers, although further information is needed about smoking habits in the meat industry. If there is a hazard infection by a papilloma virus would seem the most likely cause.