Among 489 patients with the diagnosis of bronchogenic carcinoma, there were 291 in whom surgical exploration was carried out. The carcinoma was found in a main bronchus in 71 (24%), in a lobar bronchus in 156 (54%) in a mid-lung zone in 31 (11%) and in a subpleural location in 33 (11%). The highest rate of resectability (94%) was among the 31 mid-lung carcinomas, while the subpleural group were the least favorable. The greatest rewards in resectability were thus found in the group of patients in whom bronchoscopy is always negative, the diagnosis being made by following up the suspicious shadow seen on the chest roentgenogram by exploratory thoracotomy. Operative mortalities were about the same in the four groups, but early postoperative results were best in the group with mid-lung cancer (86% of those surviving surgery being alive after one year). The "negative" chest film from previous examinations, when compared to the x-ray under consideration, supplies the key information in making an early diagnosis of lung cancer. Therefore, this film should be considered as one of the patient's most valuable possessions. If storage facilities in an x-ray department are limited, such films should be given to each patient to keep for himself.