Objective To examine rates and factors associated with adherence to annual repeat lung cancer screening in two cohorts. Participants and methods The self-pay cohort ( n = 2083) was individuals aged 40 years and older with no prior cancer and a smoking history. Participants had to obtain a prescription from their doctor for the low dose, computerized tomography scan (CT), and were responsible for payment of $300 as these CT scans are not typically covered by insurance. The no-pay cohort ( n = 1304) was individuals aged 60 and older with a smoking history, and no prior cancer. The initial and one year repeat CT were provided free of charge. Rates of adherence for each cohort were analyzed by demographic variables, smoking history, family history of lung cancer, smoking status (former/current), perceived risk and worry of getting lung cancer and baseline screening CT. Results Adherence to annual follow-up was lower for the self-pay than for the no-pay cohort (62% vs. 88%). Both the self-pay and no-pay cohorts had higher adherence rates among Caucasians and those who had a college degree. A greater perceived risk of getting lung cancer increased adherence among the self-pay cohort. Non-calcified nodules found on baseline CT increased the adherence for the self-pay cohort, but decreased the adherence for the no-pay cohort. Conclusions These findings should be used in developing educational materials and targeted retention strategies to increase adherence with repeat lung cancer screening.