A 23-day-old female baby was emergently admitted to our hospital with massive pulmonary hemorrhage due to penetration of staphylococcal abscess within left lung to pulmonary vein. Conservative therapy was so difficult that we performed left lower lobectomy on the supine position. After the operation, hypoxia continued because blood from the left lung had flown to the right lung before the operation. Pseudomonas cepacia pneumonia occurred for superinfection and developed into sepsis. On the 9th postoperative day, she died of Multiple Organ Failure. Staphylococcal lung abscess in neonate is rare, but its course is usually severe. Early diagnosis and adequate therapy is necessary. Semisynthetic-Penicillin and Cephazolin (CEZ) Resistant Staphylococcus aureus was detected in this patient, so this could have been one of the factors which led to increased severity of this infection. Semisynthetic Penicillin and CEZ Resistant Staphylococcus aureus has increased from 1980, especially in nosocomial infection. Recently we experienced twelve cases of neonatal staphylococcal infections. In these cases the resistant strain has increased. This resistant mechanism is mediated partially by β-lactamase, but mostly by abnormal Penicillin Binding Protein. Moreover there is a problem of tolerance by autolytic enzyme inhibitors (ex. Lipoteichoic acid etc.). So we use Cafmetazole or Fosfomycin as a first choice for neonatal staphylococcal infections.