A case control study of the incidence of lung, stomach, and pancreatic cancers in southern Louisiana was conducted. This area was targeted for study because significantly elevated mortality rates for these three cancers have been observed in one or more sex or race groups for several decades. Current primary lung cancer, stomach cancer, and pancreatic cancer cases were identified from admission and pathology records of all participating hospitals in 26 south Louisiana parishes. Personal interviews were conducted with 1,253 lung cancer cases and 1,274 lung cancer comparisons, 391 stomach cancer cases and 390 stomach cancer comparisons, and 346 pancreas cancer cases and 354 pancreas cancer comparisons, or their relatives if they had died. Respondents were questioned about occupation, residency, diet, smoking, coffee and alcohol consumption, water supply, and related items. An increased risk of lung cancer with increased use of cigarettes was found. An increased risk of lung cancer was found for nonsmokers married to smokers. Coffee consumption was not correlated with an increased risk of pancreatic cancer; however, an increased risk of lung cancer was associated with increased daily intake of coffee. Only close proximity to lumber mills and wood products industries was associated with an increased risk of lung cancer. Diets high in pork and nitrite containing meats and low in fruits, vegetables, and dietary vitamin-C caused a high risk of stomach cancer. Diets high in fruits and vegetables, dietary vitamin-C and dietary beta- carotene had a protective effect against lung cancer. The authors conclude that the association between lung cancer and coffee consumption is probably not causal.