The results are reported from a multicentered, randomized clinical trial of a physician-delivered smoking cessation intervention package. All physicians attended a four-hour training session during which the rationales for the different aspects of the intervention were discussed, including a detailed description of the proper use of nicotine-bearing chewing gum. Patients were randomized to receive an offer of a prescription of 2 mg of nicotine chewing gum in addition to the basic intervention (n = 111) or the basic intervention alone (n = 112). The basic intervention included advice, setting a date for quitting, self-help materials, and the offer of supportive follow-up visits. Receptionists were instructed to recruit the first two smokers attending the practice each day. One-year smoking cessation was validated by cotinine saliva analysis. The validated three-month sustained abstinence rates at one year were 8.1 percent and 9.8 percent in the gum and no-gum groups, respectively. The 95 percent confidence interval about this difference was -9.3 percent to 6.4 percent. There is no evidence from this study that the offer of 2 mg of nicotine-bearing gum enhances smoking cessation rates when added to a comprehensive intervention offered to all smokers in primary care. Until larger trials are completed, however, the possibility that this dose of nicotine gum may produce small beneficial effects cannot be excluded.