This is a report of a case of acute osteomyelitis in a 19 day old infant. Cases of osteomyelitis in childhood are not unusual, but it is felt that the occurrence of this condition during the neonatal period is rare and worthy of recording. In addition, the therapeutic value of penicillin is demonstrated in controlling the acute phase of the infection. REPORT OF CASE D. D., a white boy aged 19 days, was admitted as a Navy dependent to the pediatrie service of the Newport Hospital. Newport, R. I., because of elevated temperature and swelling of the left thigh of two davs' duration. The infant was born at full term by spontaneous delivery and weighed 7 pounds 1 ounce (3,200 Gm.). He had an uneventful, afebrile, neonatal course in the nursery and was discharged on the ninth day of life after having reached birth weight. His formula consisted of an