Ninety-four patients with roentgenographically occult bronchogenic squamous cell carcinoma had surgical resection. Fifty-three reported having no symptoms. In 83 carcinoma was detected by cytologic examination of the sputum during lung cancer screening. The carcinomas were located in segmental bronchi (34 cases), subsegmental bronchi (19 cases), divisional bronchi (17 cases), and subsubsegmental or more peripheral bronchi (15 cases). The number of cases classified by TNM staging were 16 Tis N0 M0, 72 T1 N0 M0, 4 T1 N1 M0, and 2 T2 N1 M0. Extrabronchial invasion of the resected carcinoma was observed in 17 lesions (16 cases). Five of six patients with lymph node metastasis in the resected specimens had carcinoma with extrabronchial invasion. Multiple primary lung cancers were observed in nine patients at the time of operation and in seven subsequently. Four of seven patients with subsequent primary lung cancer had surgical resection, and no recurrence was observed after the second operation. There were two deaths from lung cancer: One was caused by subsequent primary lung cancer and the other by mediastinal lymph node metastasis. In the 75 patients with intrabronchial cancer invasion and without lymph node metastasis who had complete resection, there was no local recurrence or metastasis of cancer. The 5-year survivals were 80.4% (death from all causes) and 93.5% (death from lung cancer). Although subsequent primary lung cancer is troublesome, operation is a reliable treatment for occult bronchogenic squamous cell carcinoma.