We retrospectively studied clinical cases of lung cancer complicated by pulmonary aspergillosis. A total of 19 cases with average age of 69.5 years were encountered over the last 9 years. All had a history of smoking and 18 were men. In 2 cases, pulmonary aspergillosis and lung cancer were diagnosed concurrently. Pulmonary aspergillosis was diagnosed first in 4 cases and lung cancer was diagnosed first in 13 cases, in 11 of which pulmonary aspergillosis developed after surgery for lung cancer. In the non-operated group 5 cases had complications at the same site and 3 had complications at a different site. In the operated group, 10 cases subsequently had ipsilateral pulmonary aspergillosis and 1 case had contralateral pulmonary aspergillosis. Thirteen cases received antifungal medication. Lung cancer therapy is a risk factor for pulmonary aspergillosis. Careful medication is recommended.