Antimicrobial-resistant organisms are one of the major problems dealt with in infection prevention. It is a critical issue in the field of oncology because cancer patients are frequently immunocompromised. The major techniques used for infection prevention against nosocomial infection due to antimicrobial-resistant organisms are standard precaution and contact precaution. It is also important to reduce resistant bacteria by promoting cleanliness of the hospital environment, because the hospital is a potential source of resistant bacteria. Antimicrobial stewardship is also warranted for reducing the risk of the emergence of antimicrobial-resistant organisms.