The literature on Munchausen Syndrome by Proxy (MSP) is reviewed to assess the extent of existing knowledge and the incidence of this syndrome among health care workers. Although use of this diagnosis appears to be increasing and broadening, it was not until the Beverly Allitt case in the United Kingdom in 1993 that this syndrome was used to explain the behaviour of a health care worker who harmed people in his/her care. However, a review of available details of previous health care workers accused of murder reveals that five shared some of the distinctive features of MSP. Although care must be taken when applying diagnoses, in view of the risk of morbidity and mortality which MSP poses for the people involved, it is important that health care workers become more informed and involved in understanding and detecting MSP.