There have been few national studies of the prevalence of elder mistreatment (abuse and neglect) in private households. This article provides an overview of the UK National Prevalence Study of Elder Mistreatment that took place in 2006. It addressed 2,111 respondents in four countries who answered a face-to-face survey questionnaire. The achieved sample was weighted to be representative of the UK older population. Of respondents, 2.6% reported mistreatment by family members, close friends, or care workers. The predominant type of reported mistreatment was neglect (1.1%) followed by financial abuse (0.6%), with 0.4% of respondents reporting psychological abuse, 0.4% physical abuse, and 0.2% sexual abuse. Women were significantly more likely to have experienced mistreatment than men, but there were gender differences according to type of abuse and perpetrator characteristics. Divergent patterns were found for neglect, financial, and interpersonal abuse. Further analysis of the data indicated that the likelihood of mistreatment varied with socioeconomic position and health status.