Cigarette smoking among adolescents is one of the 10 Leading Health Indicators that reflect the major health concerns in the United States. To examine changes in cigarette smoking among U.S. high school students during 1991-2001, CDC analyzed data from the national Youth Risk Behavior Survey (YRBS). This report summarizes the results of the analysis, which found that although cigarette smoking rates increased during most of the 1990s, they have declined significantly since 1997. If this pattern continues, the United States could achieve the national health objective for 2010 of reducing current smoking rates among high school students to < or = 16% (objective no. 27-2b).