The 'quit4u' stop smoking service (SSS) was developed by National Health Service (NHS) Tayside for smokers in deprived areas of Dundee (UK). quit4u combined behavioural support and pharmacotherapy with financial incentives for each week that participants remained quit. A quasi-experimental study was undertaken with smokers using quit4u between 2009 and 2011 compared with smokers using SSSs in the rest of Scotland. The outcome measures were: number of quit attempts; quit rates at 1, 3 and 12 months; cost-effectiveness. Mechanisms of change were explored through quantitative and qualitative research that explored the views and experiences of service users and professionals involved in quit4u. The number of quit attempts made using SSSs in deprived areas of NHS Tayside increased by 44% between 2007 and 2010. quit4u had significantly higher quit rates at 1 month (49.9% versus 33.7%), 3 months (30.7% versus 14.2%) and 12 months (9.3% versus 6.5%) compared with similar smokers using other SSSs. The incremental cost per quitter was £2296. A combination of elements kept clients engaged and supported quit attempts: carbon monoxide (CO) tests, financial incentives, high-quality pharmacy support, rolling groups and greater varenicline use. quit4u may provide an effective and cost-effective model for engaging and supporting smokers in deprived areas to quit.