There is some evidence to suggest that regular supervised physical activity may be useful as an aid to smoking cessation. It is unclear whether less extensive interventions confer similar benefits. This study examined whether physical activity counseling alone increases long-term smoking abstinence and physical activity levels and reduces weight gain. 299 male and female smokers were randomized to a 7-week smoking cessation program, including nicotine replacement therapy, plus either (i) physical activity counseling ('exercise', N=154), or (ii) health education advice ('control', N=145). There was no significant difference in rates of continuous smoking abstinence between the exercise group and the controls at 12 months following the quit day (9.1% versus 12.4%). Significant increases in physical activity levels observed for the exercise group versus the controls at six weeks were not maintained at 12 months. There was a non-significant tendency for less weight gain in the exercise group versus the controls at 12 months (P=0.06). Further trials are needed to examine the effect of more extensive physical activity interventions on smoking cessation, physical activity levels and post-cessation weight gain.