Given the potential advantages of online assessment of implicit alcohol-related cognitive processes, the goal of this study was to empirically validate the online administration of the implicit association test (IAT). First, we examined whether an Internet-delivered IAT programmed in Flash can be as effectively used to assess implicit alcohol-related associations as equivalent IAT versions that are programmed in local lab software, such as Inquisit. Second, participants performed the IAT versions once in the controlled laboratory setting and once on their home computers via the Internet. Findings with the alcohol IAT versions were robust and did not vary systematically with respect to setting (home or lab) or assessment software (Flash or Inquisit). Importantly, there were also indications that IAT versions performed at home were more strongly related to explicit measures and drinking behavior than were lab-based IAT versions. Together, these findings demonstrate that the alcohol IAT can be validly administered online via participants' home computers.