Hardly a series of cases of carcinoma of the lung has been reported without mention of some cases in which the duration was two years or more. In Brunn's1 series (1926) there were 20, or 7.5 per cent, of cases in which the disease had such a duration. In the reports published before 19322 it is unlikely that adenoma was differentiated from carcinoma. It seemed advisable to review our cancer material to determine whether, exclusive of possible adenoma, cancer of long duration existed. Eleven cases of cancer of a duration of more than two years, proved histologically, were encountered and studied. In the course of the study certain data were discovered which may be a clue to earlier recognition of some types of carcinoma. The age distribution of the patients was not remarkable, the ages ranging from 40 to 70. But wider variations are found in larger series.