AbstractDespite major gains in smoking cessation treatment over half of recently quit smokers will relapse within thefirst year. Two systematic reviews of relapse prevention studies came to different conclusions on effectivenessof behavioral interventions. Existing evidence in relapse prevention is limited by study designs methodologyand conceptual approaches to behavioral interventions. Different approaches to relapse prevention studiesand to the interventions themselves are needed to advance the long-term understanding and outcomes ofsmoking relapse prevention. To date relapse prevention interventions have focused on the newly abstinentsmoker (abstainer) and not attempted to directly or indirectly influence the abstainers personal network(PN) e.g. by helping the abstainer influence others in their PN to quit. Personal networks exert powerfuleffects on initiating and maintaining smoking behavior and can facilitate maintaining abstinence or triggerrelapse. A help others intervention that seeks to increase the abstainers ability to influence smokers in theirPN to quit thereby creating a PN social environment more supportive of long-term abstinence - may have abeneficial effect on relapse. The Helpers SQ intervention encourages abstainers to reinforce their ownabstinence through helping others quit and to proactively influence their PN to be more conducive to long-termsmoking abstinence. Framing relapse as a dynamic and complex process the Helpers Stay Quit (Helpers SQ)intervention is a conceptually novel approach to relapse prevention that integrates different behavioral theoriesinto a multifaceted intervention model presented as an on-line tobacco cessation brief intervention training.Helpers SQ teaches abstainers how to encourage other tobacco users to quit and avoid relapse through a non-confrontational helping conversation (HC) that encourages quitting and use of evidence-based cessation aids(e.g. quitlines cessation medications) without confrontation and nagging. Our pilot feasibility study of HelpersSQ (N=104) with abstainers from Arizonas state quitline compared 30-day abstinence at 7-months with apropensity score matched sample from quitline clients not exposed to Helpers SQ. Preliminary results: HelpersSQ participants reported higher 30-day abstinence than non-participants (82% vs. 36% Difference = 46%[95% CI: 37% 56% p<0.0001]). Encouraged by these results we hypothesize that quitline abstainers exposedto Helpers SQ will have higher 30-day and 7-day point prevalence abstinence than those receiving quitlinefollow-up usual care and that the effect of Helpers SQ may be mediated by PN characteristics. To test thishypothesis we propose a pragmatic randomized controlled trial (N=940) with embedded mixed-methods PNstudy to assess the effect of Helpers SQ training on proportion and duration of abstainers abstinence overtime and on abstainers PN interactions related to smoking and smoking cessation. Metrics derived from thePN study will be used for mediational analyses of overall and gender-based effects of Helpers SQ on smokingrelapse.