The objective of this study was to identify the most effective intervention strategies and policies for smoking cessation among adults. The Medline and Cochrane Library databases were searched, limited to publications since January 2000. A 'review of reviews' approach was followed. Systematic reviews and meta-analyses were included. Reviews aimed at adolescents or specific subgroups were excluded. Two reviewers independently assessed titles and abstracts. For every intervention strategy, only the most recent publication was included. Twenty-three studies met the inclusion criteria. The included intervention strategies and policies were ranked according to their effect size, taking into account the number of original studies, the proportion of studies with a positive effect and the presence of a long-term effect. Evidence of effectiveness for the following strategies was found: group behavioural therapy [odds ratio (OR) 2.17, confidence interval (CI) 1.37-3.45], bupropion (OR 2.06, CI: 1.77-2.40), intensive physician advice (OR 2.04, Cl: 1.71-2.43), nicotine replacement therapy (OR 1.77, CI: 1.66-1.88), individual counselling (OR 1.56, CI: 1.32-1.84), telephone counselling (OR 1.56, CI: 1.38-1.77), nursing interventions (OR 1.47, CI: 1.29-1.67) and tailored self-help interventions (OR 1.42, CI: 1.26-1.61). A 10% increase in price increased cessation rates by 3-5%. Comprehensive clean indoor laws increased quit rates by 12-38%. These results show and confirm that a wide array of effective smoking cessation intervention approaches and policies can have a large impact on smoking cessation rates.