Objectives. Smokeless tobacco has many adverse health effects. We analyzed long-term national trends in smokeless tobacco use. Methods. We used 1987 to 2000 National Health Interview Survey data for adults aged 18 years and older, 1986 to 2003 data from Monitoring the Future surveys of adolescents, and 1991 to 2003 data from the Youth Risk Behavior Survey for 9th- to 12th-grade students to examine overall and demographic-specific trends. Results. Smokeless tobacco use among adult and adolescent females was low and showed little change. Smokeless tobacco use among men declined slowly (relative decline=26%), with the largest declines among those aged 18 to 24 years or 65 years and older, Blacks, residents of the South, and persons in more rural areas. Overall and demographic-specific data for adolescent boys indicate that smokeless tobacco use increased for 12th-grade students from 1986 until the early 1990s, but has subsequently declined rapidly in all grades since then (range of relative overall declines=43% to 48%). Conclusions. Smokeless tobacco use has declined sharply, especially among adolescent boys. Ongoing prevention and cessation efforts are needed to continue this trend.