304 Background: Many centers are establishing LDCT lung cancer screening programs after the 2013 grade B recommendation from the United States Preventive Services Task Force (USPSTF). Uncertainty remains regarding the extent to which new programs will adhere to recommended selection criteria, as well as screening program performance. We analyzed adherence to selection criteria, rate of positive screens, and prevalence of incidental findings in a single-center LDCT screening registry study. Methods: We established a prospective, longitudinal registry study of patients undergoing LDCT screening at the Seattle Cancer Care Alliance. Baseline data include socio-demographic characteristics and eligibility for LDCT screening. We conduct chart reviews at 6 and 12 months to determine screening results (based on NLST definitions); lung cancer diagnosis; and incidental findings. Results: From August 2012 to April 2014, 62 out of 105 (59%) screened patients enrolled in the registry. Mean age is 62 years; 38 (61%) are male; 52 (84%) are white; mean household income is $97,363; 31 (50%) are current smokers; and 39 (63%) have a smoking history ≥ 30 pack-years. A total of 28 (45%), 31 (50%), and 31 (50%) of patients were eligible for screening based on criteria used in the NLST or recommended by the NCCN or USPSTF guidelines, respectively. Sixteen patients (26%) were not eligible for screening based on any of these criteria. For fourteen (88%) of these patients, LDCT screening was ordered by a primary care provider as opposed to a lung cancer specialist. Initial screening results were positive in 7 (13%) patients, with 1 patient diagnosed with lung cancer. At least one incidental finding was reported in 40 (74%) patients, including cardiac and pulmonary abnormalities in 28 (70%) and 25 (63%) patients. Conclusions: About one quarter of patients undergoing LDCT screening do not meet recommended criteria, with primary care providers most commonly ordering the LDCT screen for these patients. Primary care provider education may improve adherence to screening guidelines. Incidental findings were more frequently reported than in the NLST; their impact on healthcare outcomes and costs deserves further investigation.