The current incidence of neoplasms in a series of 958 persons treated in infancy and childhood for thymic enlargement was determined by a second survey 7 years after the original study in 1958. The 8 cases of thyroid neoplasms and, probably, the 5 of osteochondromas are in excess of the number of cases expected in a population of comparable size and age distribution. The total number of malignancies, however, is slightly but not significantly increased. These observations are consistent with most other studies of populations irradiated with roentgen rays in childhood. The comparatively low incidence of thyroid tumors in this series as compared with others irradiated in childhood and infancy is probably the result of careful port placement which reduced the exposure of the thyroid gland to small doses of scattered x-rays.