['A previous randomized controlled trial (RCT) of the Swedish National Tobacco Quitline detected no significant differences in smoking cessation outcomes between proactive and reactive services at 12-month follow-up. However, the response rate was only 59\xa0% and non-responders were over-represented in the proactive service. We performed a drop-out analysis to assess the smoking status of initial responders and non-responders.', 'At 29-48\xa0months after the first call, a postal questionnaire with six questions was sent to 150 random clients from the RCT database, with equal numbers from the proactive and reactive services as well as responders and non-responders at 12-month follow-up. Clients who did not return the questionnaire were contacted by telephone. The outcome measures were point prevalence (PP) and 6-month continuous abstinence (CA), and their associations with response status at 12\xa0months were assessed by logistic regression.', 'The response rate was 74\xa0% (111/150). Abstinence was significantly higher among initial responders than non-responders (PP 54\xa0% vs. 32\xa0%, p\u2009=\u2009.023 and CA 49\xa0% vs. 21\xa0%, p\u2009=\u2009.003). The odds ratios for initial responders vs. initial non-responders were, for PP\u2009=\u20092.5 (95\xa0% CI 1.1-5.6, p\u2009=\u2009.024), and for CA\u2009=\u20093.7 (95\xa0% CI 1.5-8.9, p\u2009=\u2009.004), after adjusting for proactive/reactive service.'] Are non-responders in a quitline evaluation more likely to be smokers - a drop-out and long-term follow-up study of the Swedish National Tobacco Quitline?