The colonization of methicillin-resistant Staphylococcus aureus (MRSA) was investigated in a private hospital three times for one year in an attempt to prevent the MRSA transmission. Total 22 MRSA strains were isolated. The pulse field gel electrophoresis (PFGE) was performed to investigate the route of transmission (infection way) in addition to characterize their bacteriological properties. Since the PFGE profiles were identical or very similar between the strain isolated from a patient and those from several nurses' hands and clothing cared for patient, the standard precautions including handwashing and gown technique have been performed. No transmission of MRSA through medical staff has been investigated in this hospital aftreward. Therefore, it was confirmed that the epidemiological investigation and its educational direction contribute to prevent the nosocomical infection of MRSA.