BACKGROUND: Although binge drinking (drinking five or more drinks on an occasion) is an important public health problem, little is known about which beverage types are consumed by binge drinkers. This knowledge could guide prevention efforts because beer, wine, and liquor are taxed, marketed, and distributed differently. METHODS: Data from 14,150 adult binge drinkers who responded to the Behavioral Risk Factor Surveillance System binge-drinking module in 2003 and 2004 were analyzed. Information pertained to the amount of alcohol consumed during a binge drinker's most recent binge episode, including beverage-specific consumption. RESULTS: Overall, 74.4% of binge drinkers consumed beer exclusively or predominantly, and those who consumed at least some beer accounted for 80.5% of all binge alcohol consumption. By beverage type, beer accounted for 67.1%, liquor for 21.9%, and wine accounted for 10.9% of binge drinks consumed. Beer also accounted for most of the alcohol consumed by those at highest risk of causing or incurring alcohol-related harm, including people aged 18-20 years (67.0% of drinks were beer); those with three or more binge episodes per month (70.7%); those drinking eight or more drinks per binge episode (69.9%); those binging in public places (64.4%); and those who drove during or within 2 hours of binge drinking (67.1%). CONCLUSIONS: Beer accounted for two thirds of all alcohol consumed by binge drinkers and accounted for most alcohol consumed by those at greatest risk of causing or incurring alcohol-related harm. Lower excise taxes and relatively permissive sales and marketing practices for beer as compared with other beverage types may account for some of these findings. These findings suggest that equalizing alcohol control policies at more stringent levels would be an effective way to prevent excessive drinking.