Objectives: To identify the impact of a smoking cessation programme on social and ethnic inequalities in smoking rates through social and ethnic differences in enrolment and quitting. Methods: Analysis of records of 11325 patients who enrolled in an innovative smoking cessation programme in Christchurch, New Zealand between 2001 and 2006. We compare enrolment, follow-up, quitting and impact on population smoking rates in the most and least deprived neighbourhoods and the neighbourhoods with the lowest and highest proportions of Māori, the indigenous people of New Zealand. Results: Enrolment as a proportion of the population was higher from the most deprived areas but as a proportion of neighbourhood smokers, it was lower. Enrolees from the least deprived quintile were 40% more likely to quit than those from the most deprived quintile. Smoking rates were 2.84 (2.75 to 2.93) times higher in the most deprived neighbourhoods. If the programme had not been available we estimate that this differential would have reduced to 2.81 (2.72 to 2.90). Thus the programme made no difference to deprivation related inequalities. In neighbourhoods with the highest proportion of Māori, smoking rates were 2.33 (2.26 to 2.41) times higher and we estimate that without the programme smoking rates would be 2.30 (2.23 to 2.37) times higher. Ethnic inequalities were also not changed by the programme. Conclusions: Although enrolees were drawn from a wide variety of backgrounds, those most likely to quit tended to reside in affluent areas or areas with a low proportion of Māori. There was no evidence that this smoking cessation program increased or decreased inequalities within the Chirstchurch population. For smoking cessation programmes to have an impact on health inequalities more effort is required in targeting hard to reach groups and in encouraging them to quit.