To identify risk factors for adenocarcinoma of the lung, a population-based case-control study of 336 female cancers of this cell type and an equal number of neighborhood controls was conducted between 1983 and 1986. After adjusting for personal smoking, personal and family histories of lung disease emerged as additional risk factors. A personal history of any lung disease was associated with a 40% increase in risk [smoking adjusted relative risk (SARR) = 1.4, 95% confidence interval (CI) = 1.0, 2.0] with a more marked increase in risk for lung diseases occurring during childhood (SARR = 1.9, 95% CI = 1.2, 3.2) and for tuberculosis (SARR = 10.0, 95% CI = 1.1, 90.1). Family histories of tuberculosis (SARR = 2.0, 95% CI = 1.1, 3.6) and of lung cancer (SARR = 3.9, 95% CI = 2.0, 7.6) were also risk factors for adenocarcinoma of the lung. Increasing risk was observed with decreasing intake of dietary beta-carotene. After adjusting for personal smoking, women in the lowest quartile of intake showed a two-fold increased risk relative to those in the highest quartile of intake (P = 0.003). There were also some suggestive differences between cases and controls in their reproductive history and hormone use.