BACKGROUND Physicians prescribing nicotine replacement therapy (NRT), or health plans covering NRT, often want their patients to receive adjuvant behavioral treatment. However, how to do that in a "real world" is unclear. This paper reports results from a public health program that uses proactive telephone counseling as support for physician advice and provides adjuvant treatment for NRT users. METHODS Participants were NRT users (N = 8,832) who called the California Smokers' Helpline, a statewide cessation service that provides proactive counseling, one session before NRT use and multisessions after the smokers received NRT. After receiving NRT, some participants discontinued the counseling while others continued with follow-up sessions. A subset of the 8,832 participants (n = 664) was interviewed 13 months later for quitting status. RESULTS After receiving NRT, 79% of the participants continued with counseling and received 4.2 sessions on average, while 21% of them received only one session. Overall, 82.8% of all participants made a quit attempt. Nicotine patch users were more likely to make an attempt than nicotine gum users (85.2% vs 66.3%), but the relapse probability was the same for these attempts. Those who received multiple counseling were more likely to make an attempt than those receiving single counseling (84.4% vs 77.1%) and were more likely to stay quit for 1 year (25.6% vs 16.1%). CONCLUSIONS Proactive telephone counseling is a promising adjuvant treatment for NRT users in a "real-world" setting: a convenient referral service for supporting health plans or physicians who advise their patients to quit smoking.