We tested whether a 3-month beneficial effect of telephone counseling as an adjunct to the use of medications for smoking cessation was maintained through 12 months. Health plan members filling a prescription for cessation medications were randomized either to a no-contact control group or to proactive recruitment into telephone counseling. An increased point-prevalence quit rate at 3 months (33.1% vs. 27.4%, p<.05) among smokers randomized to proactive recruitment for telephone counseling was not maintained. Although at 12 months smokers in the proactive recruitment arm were more likely to report a 24-hr quit attempt, compared with control group smokers (86.7% vs. 80.8%, p = .027), we found no differences between the groups in repeated (3-month and 12-month) 7-day point-prevalence quit rates. In an analysis of predictors of quitting, age, marital status, making a lifestyle change, and the presence of household smokers were associated with repeated 3-month and 12-month point-prevalence abstinence. Offering telephone counseling to insured smokers who have filled prescriptions for cessation medications did not increase long-term quit rates. Although other variations of this approach might be tested, we suspect that it might be more useful to test innovative ways to influence the factors we identified as being most strongly predictive of lack of successful quitting.