In recent years, studies have shown that low-dose computed tomography (LDCT) is a safe and effective way to screen high-risk adults for lung cancer. Despite this, uptake remains low, especially in limited-resource settings. The American Cancer Society (ACS) partnered with two federally qualified health centers and accredited screening facilities on a 2 year pilot project to implement an LDCT screening program. Both sites attempted to develop a referral program and care coordination practices to move patients through the screening continuum and identify critical facilitators and barriers to implementation. Evaluators conducted key informant interviews (N = 46) with clinical and administrative staff, as well as regional ACS staff during annual site visits. The Consolidated Framework for Implementation Research guided our analysis of factors associated with effective implementation and improved screening outcomes. One study site established a sustainable lung screening program, while the other struggled to overcome significant implementation barriers. Increased time spent with patients, disruption to normal workflows, and Medicaid reimbursement policies presented challenges at both sites. Supportive, engaged leaders and knowledgeable champions who provided clear implementation guidance improved staff engagement and were able to train, guide, and motivate staff throughout the intervention. A slow, stepwise implementation process allowed one site's project champions to pilot test new processes and resolve issues before scaling up. This pilot study provides critical insights into the necessary resources and steps for successful lung cancer screening program implementation in underserved settings. Future efforts can build upon these findings and identify and address possible facilitators and barriers to screening program implementation. [ABSTRACT FROM AUTHOR]