Reducing youth access to commercial sources of alcohol is recognized as a necessary component of a comprehensive strategy to reduce underage drinking and alcohol-related problems. However, research on policy-relevant factors that may influence the commercial availability of alcohol to youth is limited. The present study examines characteristics of off-premise alcohol outlets that may affect alcohol sales to youth. Random alcohol purchase surveys (N = 385) were conducted in 45 Oregon communities in 2005. Underage-looking decoys who were 21 years old but did not carry IDs were able to purchase alcohol at 34% of the outlets approached. Purchase rates were highest at convenience (38%) and grocery (36%) stores but were relatively low (14%) at other types of outlets (e.g., liquor and drug stores). Alcohol purchases were less likely at stores that were participating in the Oregon Liquor Control Commission's Responsible Vendor Program (RVP), when sales clerks asked the decoys for their IDs, and at stores with a posted underage alcohol sale warning sign. Alcohol purchases were also inversely related to the number of sales clerks present in a store, but were not related to sales clerks' age and gender. Findings of this study suggest that more frequent compliance checks by law enforcement agents should target convenience and grocery stores, and owners of off-premise outlets should require training of all sales clerks to ensure reliable checks of young-looking patron IDs, and should post underage alcohol sales warning signs in clear view of patrons.