Cigarette use is the leading preventable cause of death in the United States. A national health objective for 2010 is to reduce the prevalence of current cigarette use among high school students to </=16% (objective no. 27-2b). To examine changes in cigarette use among high school students in the United States during 1991-2005, CDC analyzed data from the national Youth Risk Behavior Survey (YRBS). This report summarizes the results of that analysis, which indicated that, although lifetime, current, and current frequent cigarette use was stable or increased during the 1990s and then decreased significantly from the late 1990s to 2003, prevalence was unchanged during 2003-2005. To achieve the 2010 objective, the downward trend in youth smoking must resume.