Adverse childhood experiences (ACEs) include verbal, physical, or sexual abuse, as well as family dysfunction (e.g., an incarcerated, mentally ill, or substance-abusing family member; domestic violence; or absence of a parent because of divorce or separation). ACEs have been linked to a range of adverse health outcomes in adulthood, including substance abuse, depression, cardiovascular disease, diabetes, cancer, and premature mortality. Furthermore, data collected from a large sample of health maintenance organization members indicated that a history of ACEs is common among adults and ACEs are themselves interrelated. To examine whether a history of ACEs was common in a randomly selected population, CDC analyzed information from 26,229 adults in five states using the 2009 ACE module of the Behavioral Risk Factor Surveillance System (BRFSS). This report describes the results of that analysis, which indicated that, overall, 59.4% of respondents reported having at least one ACE, and 8.7% reported five or more ACEs. The high prevalence of ACEs underscores the need for 1) additional efforts at the state and local level to reduce and prevent child maltreatment and associated family dysfunction and 2) further development and dissemination of trauma-focused services to treat stress-related health outcomes associated with ACEs.