A 66-year-old man who complained of cough and haemoptysis had a cavitary lesion with the meniscus sign in the right lower lung field on his chest X-ray and CT scan. He had smoked 40 cigarettes daily, for about 46 years. Initially, he was diagnosed with aspergilloma and given an antifungal agent. After 2 months, the cavitary lesion showed a slight irregularity of the inner border. The walls were irregularly thickened and were surrounded by infiltrative densities compared with the previous chest radiograph. Enlargement of right hilar and mediastinal lymph nodes was also observed. The fungus ball-like shadow was fixed on the anterior wall of the cavity and its position was not altered with the patient's movements. These radiographic findings led to suspicion that the lesion might be malignant. Transbronchial lung biopsy of the cavity wall and CT guided needle aspiration biopsy of the fungus ball-like lesion were performed. Microscopic examination revealed a squamous-cell carcinoma in both the cavity wall and the fungus ball-like lesion. There was no evidence of fungal elements. In conclusion, the meniscus sign is most often associated with benign diseases such as aspergilloma, however, one should remember that carcinoma may be a cause.