PROJECT SUMMARY Implementing effective tobacco cessation programs within LDCT lung cancer screening is needed as quitting smoking increases life expectancy, decreases risk of competing causes of death, improves length of survival among lung cancer patients, and maximizes the cost-effectiveness of lung cancer screening. Our research team, including experts in smoking cessation, lung cancer screening, and implementation science, will: (1) evaluate a multi-faceted training program to improve short-term smoking cessation rates and sustained abstinence among 1,114 patients who present for LDCT lung cancer screening in 22 community-based practices using a cluster, randomized control trial design; (2) characterize the adoption and adaptation of evidence-based tobacco cessation strategies within community-based LDCT lung cancer screening programs using extensive qualitative data, including analysis of strategic planning documents, a team blog and performance coaching notes, key informant interviews, and observational data; and (3) develop and evaluate an implementation toolkit that explains how to integrate evidence-based tobacco cessation strategies in community-based LDCT lung cancer screening programs in absence of the research team. The majority of lung cancer screening will occur in non-academic, community-based settings with diverse patient populations who are at high risk for lung cancer and other smoking-related illnesses. This effectiveness-implementation hybrid design is intended to promote the rapid translation of the evidence-based tobacco cessation strategies into community-based practices offering LDCT lung cancer screening to reduce smoking-related morbidity and mortality.