In 1984, the National Minimum Drinking Age Act (Public Law 98-363) was passed, requiring states to raise to 21 years the minimum age to purchase and publicly possess alcohol. Although the law has contributed to substantial reductions in underage drinking and alcohol-related motor-vehicle crashes, alcohol use and binge drinking rates among youths remain high in the United States, and efforts by youths to purchase alcohol from licensed establishments frequently are successful. To reduce alcohol sales to persons aged <21 years in Concord (2000 population: 40,687), New Hampshire, the Concord Police Department (CPD) and New Hampshire Liquor Commission (NHLC) conducted a pilot program of enhanced law enforcement with quarterly compliance checks of alcohol licenses during March 2002-February 2004. This report summarizes the results of that program, which indicated that enhanced enforcement 1) resulted in a 64% reduction in retail alcohol sales to underage youths and 2) was temporally associated with declines in alcohol use and binge drinking among Concord high school students. These findings emphasize the potential effectiveness of enhanced enforcement of minimum drinking age laws to reduce consumption of alcohol by underage youths.