The Committee for Prevention of Nosocomial Infection organized by national university hospitals has developed guideline for preventing hospital acquired infections. This was developed after intensive and systematic reviews of the existing scientific papers, followed by a consensus meeting with presence of the infection control specialists. The guideline consisted of following categories: standard precaution, causality organism, urinary tract infection, ventilator associated pneumonia, surgical site infection, catheter related bloodstream infection, and accidental contamination by needles. We also plan to evaluate the effectiveness of this guideline, and continue to update it by our consistent review of scientific papers.