To examine the ability of a simple system-wide screening assessment tool, an expanded vital sign stamp, to increase rates of smoker identification, physician advice to quit smoking, and physician assistance in quitting and abstinence rates. This study is a pretest, posttest design in which 5 primary health care clinics were randomly assigned to either the intervention condition, which received the vital sign stamp, or the control condition. Participants (N = 9439) were surveyed by using exit interviews at the 5 clinics, both before and after the vital sign intervention was implemented. Participants who were identified as smokers were then contacted 1 year later for follow-up. The study began in February 1995, and all follow-up visits were completed by December 1998. Implementation of the vital sign stamp significantly increased the rates at which physicians asked participants about their smoking status (17.2% vs 7.5%). However, the rates of physicians advising smokers to quit, assisting them in quitting, and arranging follow-up either stayed constant or decreased. The number of quit attempts and abstinence rates also stayed constant. A simple system-wide screening assessment tool, while effective in identifying more tobacco users, did not increase the rates at which physicians advised or assisted smokers to quit. Further system-wide changes may be needed to ensure that effective tobacco-dependence treatments are given to smokers.