A few investigators have suggested a possible association between lung cancer and a pulmonary bulla. But its correlation is not yet fully understood. Five hundred and forty-five cases with primary lung cancer were studied retrospectively by re-evaluation of their chest computed tomography (CT)-scans. Cancer adjoined a bulla in 19 cases. In these instances, each case's clinical course, pathological findings and surgical results were investigated. All cases were men and were heavy smokers. Three of them were under 50 years of age. Bulla/cancer incidence was 3.5%. Initial symptoms were common respiratory symptoms in five cases (26.3%) and hemosputa and hoarseness in one case (5.3%), respectively. In comparison with the control group, a ratio of squamous cell carcinoma (SCC) and large cell carcinoma was significantly high (P<0.05) and differentiation of the carcinoma was poor (P<0.001). Although the pathological staging and lung function data revealed no statistical difference, the survival curve of bulla/cancer group was significantly worse (P<0.01). Primary lung cancer adjoining pulmonary bulla tends to be poor in prognosis, even if it was small in size. A low-density mass shadow adjoining the bulla should be frequently examined by CT-scans and should proceed to an exploratory thoracotomy if it have increased in size.