Open brochus with diffuse narrowing, stretching, and leafless tree appearance of the bronchi is the well known bronchographic criterior of bronchioloalveolar carcinoma. Though similar findings are expected in CT, authors could find no report concerning the open bronchus sign of bronchioloalveolar carcinoma demonstrated by CT. Authors presents CT of bronchioloalveolar carcinoma showing lobar or segmental distribution and patent bronchus within the tumor mass.