Lung cancer in Xuan Wei (XW), China has been linked to exposure to unvented coal smoke and adenocarcinoma, especially bronchioloalveolar carcinoma, is most common. p53 mutations occur commonly in lung cancers and usually generate detectable levels of p53 protein accumulation. Sputum is noninvasive to collect and ideal for screening p53 abnormalities. p53 protein accumulation was detected by immunohistochemistry in lung tumors and sputa from XW lung cancer patients to determine (1) the role of p53 in lung pathogenesis, and (2) feasibility of detecting p53 protein accumulation in sputum, p53 protein accumulation was detected in 73% (22/30) of lung adenocarcinomas from XW females exposed to coal emissions and significantly higher than the control cases (33%, p < 0.05). In sputum, we detected p53 overexpression in tumor cells in 54% (13/24) of XW cases and also in dysplastic cells (50% or 4/8). These findings suggest that p53 abnormalities is important in XW lung cancer etiology.