Bronchioloalveolar carcinoma (BAC) is a histological subtype of adenocarcinoma of the lung, which is divided into 3 types: non-mucinous, mucinous and mixed type. BAC is histologically defined as "an adenocarcinoma with a pure bronchioloalveolar growth pattern and no evidence of stromal, vascular or pleural invasion." Tumors showing a solitary nodule are recognized by ground-glass opacity on chest CT. Because surgical treatment for these cases results in a good outcome, more non-invasive procedures of surgical intervention, a limited resection and video-assisted endothoracic operation, have been investigated. There is no effective therapy for patients with BAC presenting multiple nodules or tumors resembling lobar pneumonia. Recently, the effectiveness of molecular targeting therapy (gefitinib, erlotinib) for BAC is reported.