Clinical trials rigorously demonstrate the efficacy of new products and justify their marketing. However, it is only after use in real-life settings that the clinical value (effectiveness) of a new treatment is fully known. The purpose of this review was to summarise the effectiveness data for bupropion SR as an aid to smoking cessation. Available reports of effectiveness data for bupropion SR were obtained from the literature, presentations at smoking cessation meetings and from the manufacturer. Twelve sources of effectiveness data were found and included clinical practice trials, observational studies/surveys, motivational support programme results and employer-based cessation programme results. The 6-month point prevalence smoking cessation rates ranged from 25 to 49%. There is a growing body of evidence supporting the effectiveness of bupropion SR as an aid to smoking cessation. Real-life quit rates for bupropion SR are similar to those seen in the original clinical trial programme.