The purpose of this study is to describe variables associated with injury in an emergency room (ER) sample that is representative of an entire U.S. county. A probability sample (n = 3717) of ER patients from the county hospital, 3 of the 6 community hospitals, and the three health maintenance organization hospitals in a single Northern California county were breath-analyzed and interviewed at the time of the ER visit. Injured were most likely to consume only 1 or 2 drinks within < 1 hr of injury occurrence. Twenty-three percent reported feeling drunk at the time of the event, and of these, 45% felt the event would not have happened if they had not been drinking. Breathalyzer reading, feeling drunk at the time of the event, and quantity-frequency (Q-F) of usual drinking were found to be predictive of admission to the ER with an injury, whereas breathalyzer reading, Q-F, and being injured in someone's home were predictive of reporting drinking prior to injury. Although feeling drunk at the time of the event and usual drinking patterns are predictive of injury occurrence, drinking prior to the event may not entail large quantities of alcohol consumed, but relatively small amounts consumed in close proximity to the injury event. These alcohol consumption variables may vary, however, depending on the type, cause, and severity of injury.