The authors examined the ownership of false identification (fake ID) for the purpose of obtaining alcohol and the relation of fake ID ownership to heavy drinking in a longitudinal sample of college students under 21 years of age. A sample of 3,720 undergraduates was assessed the summer prior to college entrance and during the 4 semesters comprising freshman and sophomore years. Regression analyses were used to estimate bidirectional relations between consumption and fake ID ownership. Sex, Greek membership, and prior drinking were controlled. Results showed that fake ID ownership increased over time (12.5% precollege to 32.2% fourth semester) and that Greek members were more likely than others to own fake IDs. Fake ID ownership predicted concurrent and next-semester heavy drinking with increasing strength over time. Also, the acquisition (onset) of fake ID ownership at each time point was predicted by previous-semester consumption. When traditional, robust risk factors of consumption are controlled, fake ID ownership meaningfully relates to heavy drinking in college. It thus presents a significant public health problem, addressable through training for alcohol servers and retailers, punitive measures toward fake ID owners, and other possible interventions.Keywords false identification; heavy drinking; alcohol access; longitudinal Heavy drinking is pervasive in college, with 42% of students in a nationally representative sample reporting having had five or more drinks in a sitting within 2 weeks in 2004 (Johnston, O'Malley, Bachman & Schulenberg, 2005), a prevalence rate that has not much changed over the last 25 years. Students experience a wide range of negative short-and long-term personal consequences from heavy drinking (Jackson, Sher & Park, 2005; Task Force of the National Advisory Council on Alcohol Abuse and Alcoholism, 2002), and heavy drinking also presents significant second-hand effects on other individuals and the larger community (Wechsler, Moeykens, Davenport, Castillo, & Hansen, 1995). Compounding the problem of heavy drinking in college is the fact that many heavy drinking college students are below the age of 21 years, the current legal drinking age in the United States, presenting significant enforcement challenges for college campuses and the communities in which they are situated. Indeed, illegal purchase and possession of alcohol is a problem in its own right, as violations of liquor laws accounted for 15% of all arrests among youth aged 18 to 20 years in 2003 (Federal Bureau of Investigation, 2003 Federal Bureau of Investigation, 2004) Although underage college students are less likely to be drinkers than their college peers aged over 21 years of age (77% vs. 86% past-year consumption of any alcohol, odds ratio [OR] = . 56), they were more likely to report that they typically engaged in binge drinking on occasions when they did consume alcohol (58% men and 32% women vs. 42% men and 21% women; men OR = 1.93, women OR = 1.85), where binge drinking was defined as five or more drink...