"Drink spiking" is the term used for adding drugs and/or alcohol to a drink without the knowledge or consent of the person consuming the drink. The potential consequences of drink spiking can be severe, both physically and emotionally, depending on the type and amount of additive used and the intent of the perpetrator. Data for this study were obtained directly from victims of drink spiking, police records in each Australian jurisdiction, the Center Against Sexual Assault, and the national Drink Spiking Hotline. The hotline operated for 1 month between November and December 2003 and obtained reports from 201 people who claimed to be victims of drink spiking or people calling on their behalf. Because of the absence of exact numbers on the prevalence of drink spiking, this study used a procedure that inflated the number of incidents reported to the police by the level of underreporting found in self-report victim surveys. This produced an estimate that between July 1, 2002, and June 30, 2003, there were 3,000-4,000 suspected incidents of drink spiking in Australia. Approximately one-third of these incidents involved a subsequent sexual assault by the drink-spiking perpetrator; between 60 and 70 percent of the spiking incidents involved no additional victimization. Four out of five victims were female. It is estimated that less than 15 percent of suspected drink-spiking sexual assaults were reported to police, and between 20 and 25 percent of spiking cases that involved no sexual assault were reported to police. Alcohol was the predominant drug used in spiking. Needs identified in the study include greater public awareness of the importance of reporting drink spiking to police, the need for victims to seek medical assistance as soon as possible, the need for improved procedural responses to spiking incidents, and improved data-collection methods. 18 tables, 9 figures, 84 references, and appended organizational resources and descriptions of types of drugs commonly associated in the media with drink spiking