Suppurative arthritis of the hip is a serious lesion in premature and fullterm infants in the neonatal period. Septicemia, the precursor to hip-joint suppuration, is difficult to recognize at this age. The clinical manifestations of septicemia in the neonatal period are reviewed. Hemolytic Staphylococcus aureus was the most common organism recovered from the blood stream and the hip joint. It was found in five of the six premature infants and in seven of the nine full-term infants, including one with bilateral hip involvement. In fifteen hips hematogenous osteomyelitis of the intracapsular portion of the femur (eleven hips) and of the ilium (four hips) was the source of the joint pus. In the one hip that showed no focus of involvement in the bone, the hemolytic streptococcus infection may have reached the joint by synovial implantation of organisms. Subluxation or pathological dislocation of the hip was seen on roentgenograms in all the infants in this group. In twelve hip joints infected with hemolytic Staphylococcus aureus, eight femoral heads disappeared. In all eight there was a delay of from four to sixteen days from the onset of hip-joint suppuration to local treatment of the hip, either by surgical drainage or by repeated aspiration and instillations of penicillin. The most important factors in saving the cartilaginous femoral heads in infected hip joints in the neonatal period are early diagnosis and prompt evacuation of pus, preferably by surgical incision and drainage. Systemic antibiotics proved to be effective in controlling septicemia and osteomyelitis, but they were unable to sterilize the infected hip joints. Antibiotics could not take the place of surgical drainage.