The aim of the present study was to assess changes of cell membrane antigens on neutrophils in septic patients. Expression levels of neutrophil membrane antigens were measured employing a FACS calibur flow cytometer with several fluorescence-labeled monoclonal antibodies. Expression levels of the CD14 antigen were higher in patients with sepsis than in healthy individuals. In particular, the expression levels of CD14 increased in patients complicated by septic shock. Expression levels of TLR-4 were higher in patients with sepsis or septic shock than in healthy individuals. Expression levels of CD11b and CD16 were lower in patients with sepsis or septic shock than in healthy individuals and were even lower in those complicated by septic shock. Expression levels of neutrophil membrane antigens in patients with sepsis markedly changed in the acute phase. However, these levels tended to return to those of healthy individuals in the convalescing phase. Analyses of the surface antigens on neutrophils strongly involved in biological defense or tissue injury are informative for understanding the pathology of sepsis and for conducting therapy targeting neutrophils in the future.