Telephone counseling is a popular modality for smoking cessation treatment; however, little attention has been paid to evaluating the efficacy of different contents of calls. This study compared 2 types of proactive telephone calls following a group program. Participants were randomized to receive either: (a) basic content, consisting primarily of support; or (b) enhanced content, tailored to the stage of cessation (still smoking, abstinent, or relapsed) and targeting factors hypothesized to be related to success (motivation, self-efficacy, and negative mood). There was a significant interaction between treatment condition and gender. For men, the enhanced condition produced better abstinence rates through 15 months and lower relapse rates. For women, the basic condition was better. History of depression did not interact with condition.