The 2001 Harvard School of Public Health College Alcohol Study surveyed students at 119 4-year colleges that participated in the 1993, 1997, and 1999 studies. Responses in the 4 survey years were compared to determine trends in heavy alcohol use, alcohol-related problems, and encounters with college and community prevention efforts. In 2001, approximately 2 in 5 (44.4%) college students reported binge drinking, a rate almost identical to rates in the previous 3 surveys. Very little change in overall binge drinking occurred at the individual college level. The percentages of abstainers and frequent binge drinkers increased, a polarization of drinking behavior first noted in 1997. A sharp rise in frequent binge drinking was noted among students attending all-women's colleges. Other significant changes included increases in immoderate drinking and harm among drinkers. More students lived in substance-free housing and encountered college educational efforts and sanctions resulting from their alcohol use.