The study reported here is concerned with the diagnosis, treatment and end results of 61 colonic carcinomas less than 2.5 cm. in diameter. The patients were examined and treated at the Mayo Clinic during the years 1909 to 1934 inclusive. This investigation was prompted by a discussion of the advisability of extensive and radical resection for such small lesions. The lesions varied from 0.5 to 2.5 cm. in diameter, the average being about 1 cm.; lesions of no one size predominated. Pedumculated polypoid growths and carcinomas arising in association with multiple polyposis were not considered in this series. Thirty-four of the 61 patients were women and 27 were men. The youngest was 30 years of age and the oldest 75; the average age was 54 years. The average duration of symptoms was eight months and three weeks; the longest was three years and the shortest three weeks. Although the lesions