The health care setting, and most notably dental clinics, may hold promise in delivering effective tobacco intervention to adolescents. Adolescents between the ages of 14 and 17 were randomly assigned to brief advice from dental hygienists and dentists only or to brief advice plus a motivational interview and follow-up telephone contact from a study hygienist. Due to difficulties in identifying and recruiting subjects, study goals were expanded from cessation only to cessation and prevention. No differences in smoking prevalence were found between treatment conditions at either 3- or 12-month follow-up. Firm conclusions cannot be drawn about the effectiveness of treatment due both to problems in enrolling subjects and limited implementation of the motivational intervention.