This article examines the management of outbreaks of multi-drug resistant (MDR) Acinetobacter in hospitals. It briefly describes the organism and its properties and then discusses its role in disease and the risk to hospital patients, routes of transmission and patient reservoirs, mechanisms of drug resistance and susceptibility to antimicrobial agents, and measures for controlling outbreaks in hospitals. The success of these measures is illustrated by a detailed review of the control of an outbreak of MDR Acinetobacter baumannii infection in an intensive care unit in a London teaching hospital without closure of the ward or isolation of the patients.