The current study assessed features associated with drink spiking, or the adding of a substance to another person's drink without the consumer's knowledge or consent. A sample of 805 Australians, aged 18-35 years, completed a survey designed to measure the occurrence and predictors of the perpetration and victimisation of drink spiking. Almost half of the sample reported at least one experience of purchasing or mixing cocktails for others (49% and 45%, respectively), while smaller proportions reported adding alcohol to punch (26%) and adding alcoholic shots to alcoholic beverages belonging to other people (16%). A number of participants also reported previous experience of adding alcoholic shots to non-alcoholic beverages (6%), adding prescription or illicit substances to alcoholic beverages (1%), adding substances to non-alcoholic beverages (1%), and adding substances to punch (1%). Purchasing or mixing cocktails for others, adding alcohol to punch, or adding alcoholic shots to alcoholic beverages were predicted by beliefs that deliberately causing intoxication in others is acceptable and that alcohol consumption by others is indicative of their sexual attraction to participants. Engagement in these behaviours was also predicted by participants' illicit substance use and participation in casual sexual activity. Adding prescription or illicit substances to other people's beverages, or adding alcoholic shots to non-alcoholic beverages, were predicted by the belief that alcohol consumption increases one's confidence and sexual responsiveness, and by participants' use of narcotics and sedatives. Perpetrators were predominantly motivated by a wish to have fun or to increase the likelihood of engaging in consensual sexual activity. With regard to victimisation of drink spiking, 26% of the sample reported at least one victimisation. The majority of incidents occurred in licensed venues, after the participant had engaged in such low supervisory behaviours as leaving their drink unattended or accepting a drink without observing its preparation. Most participants established a belief that they had been spiked after experiencing a degree of intoxication that was beyond their expected level (based on the amount of alcohol consumption), or after experiencing such physiological symptoms as vomiting, hallucinations, lack of coordination, or unconsciousness. Despite such experiences, 85% of victims did not report the incident to authorities. Victimisation in general was predicted by participants' use of stimulant and hallucinogenic substances. Female victimisation was predicted by previous episodes of victimisation of oral sexual assault. Victimisation was not affected by participants' degree of supervision of their drinks. These findings provided empirical evidence that drink spiking is committed primarily for the purposes of creating a fun, entertaining situation. However, it was also apparent that drink spiking is perpetrated in an attempt to encourage participation in consensual sexual activity; this was particularly the case in incidents involving the addition of substances, as opposed to alcohol, to beverages belonging to others. Conclusions regarding the motivations held by perpetrators of drink spiking and the post-spiking experiences of victims informed the provision of recommendations for intervention for victims and prevention programs aimed at reducing the incidence of victimisation in the future.