Background: In 2014 and 2015, the Affordable Care Act required coverage of, and CMS began reimbursing for lung cancer screening (LCS). Previous studies have shown that when new screening tests or treatments become available, disparities in disease outcomes often increase due to those with fewer resources having less access and greater barriers to care. African American men have historically had higher incidence of and death due to lung cancer than white males in the U.S., raising concerns regarding access to LCS and the potential for increases in disparities in lung cancer. We aimed to determine whether individual or neighborhood level factors were associated with completion of a baseline screening after an order for LCS low dose CT (LDCT) was placed. Methods: In a retrospective study conducted within the five health systems of the Lung Population-based Research to Optimize the Screening Process (PROSPR) Consortium, we determined adherence to baseline LDCT after a health care provider placed an order for LCS (January 2014 through June 2019). Follow-up was available through September 2019. Patients of interest for this analysis were current or former smokers, age 55 to 80 with a 30+ pack-year smoking history. Smoking history and other individual level variables were determined through electronic medical records. Neighborhood factors were derived from the 2010 Census and multivariable logistic regression was used. Results: Of the 13,920 patients that had at least one order for a baseline LCS exam, 14.1% were non-Hispanic Black, 70.3% were non-Hispanic White, and 15.7% were of other or unknown race. Overall, 61.2% of patients completed a LDCT within 90 days and 71.9% completed a scan by the end of follow-up. Completion of a baseline scan differed by health system (LDCT at 90-days, range 51% - 84%, p<0.0001) and increased in general across scan year (range 49.1%-66.0%, p <0.001). In multivariate logistic regression models, males (aOR=1.15, 95% CI 1.07-1.23, p=<0.0001), former smokers (aOR=1.31, 95% CI 1.21-1.40, p <0.0001), and those with a prior history of any cancer (aOR=1.16, 95% CI 1.02-1.32, p=0.03) were more likely to complete LDCT. Blacks were marginally less likely to have completed a baseline LDCT (aOR=0.90, 95% CI 0.81-1.00, p=0.06) within 90 days of an order. Sex modified the associations of race on completion of orders (p=0.08) (Black men aOR=0.81, 95% CI 0.70-0.94, p=0.006 ; Black women aOR=0.99, 95% CI 0.86-1.14, p=0.89). Conclusions: This multisite study indicates Black men in particular may have a lower likelihood of completing a baseline LCS after an order for screening is placed. As lung cancer screening programs move forward, attention should be given to factors associated with reduced uptake and adherence of screening to ensure disparities in lung cancer outcomes do not persist and increase. Provider and health system factors that may impact LCS uptake should be explored in future studies.