Hypertrophic osteoarthropathy is defined as a syndrome consisting of clubbing of the digits and ossifying periostitis, primarily of the long tubular bones, occurring as the sequel of a major visceral disorder, usually intrathoracic in location. Several publications in recent years (8, 17) have emphasized the significance of periosteal new bone formation in adults and the possible relationship of this finding to bronchogenic carcinoma. Hypertrophic osteoarthropathy is also not infrequently seen in adults in association with chronic suppurative lung disease. In patients of the pediatric age group, however, the condition has received little attention. A decade passed between the two most recently published cases (7, 9) in the American and British literature, and Caffey (2) states that the condition must be rare in this country. A search of the American and British literature has revealed 8 case reports of hypertrophic osteoarthropathy in children up to the age of twelve. None of the cases are to be found in the radiologic literature, and only 5 (18, 10, 11, 7, 9) are accompanied by radiologic proof of the diagnosis. Two (1, 3) of the remaining 3 cases, on the basis of clinical criteria, appear to be valid instances of the condition, while the remaining case (13) is doubtful, since only digital clubbing is reported. The data on the 7 cases with periosteal changes are summarized in Table I. Three reports of cases in the adolescent age group were found. Two of these were in fourteen-year-old boys, one associated with widespread tuberculosis (12) and the other with carcinoma of the thymus (16). The third patient was a fifteen-year-old girl with extensive tuberculosis (5). It is proposed at this time to present 2 cases of hypertrophic osteoarthropathy in children seen at the University of Mississippi Medical Center. Case Reports CASE I: A colored girl, 3 years and 10 months of age, was admitted on Sept. 26, 1958, with a history of“a cold all her life" and“sores on the body.” Almost since birth upper and lower respiratory complaints had been present, characterized by rhinor-rhea and cough productive of thick, green mucoid material, with episodes of fever. The sores were described as large vesicles which ruptured and became pustular, with improvement in the winter and recrudescence in the spring and summer. The child had generally failed to thrive and was slower in development than her siblings. On admission the temperature was 100.0°, pulse 152, respirations 36. The weight was 16 pounds 5 ounces, and the general appearance was that of a poorly developed, poorly nourished, chronically ill child. Crusted, excoriated lesions draining purulent material were seen on the extremities, trunk, face, and scalp. Physical signs of consolidation were present over the left lung field, with scattered inspiratory râles over the right lung field.