Injecting drug users may now be the largest group at risk for contracting HIV, mainly through the sharing of drug injection equipment (including lending, borrowing, and renting). This article presents the results of an ongoing ethnographic study into the drug-taking rituals of heroin addicts. A possible additional route of HIV contamination is presented, namely the ritual sharing of drugs through a practice termed "frontloading," which is embedded in a broader pattern of the sharing of resources among addicts. It is hypothesized that in the Netherlands this practice may be responsible for a substantial proportion of HIV spread among injecting drug users.