BACKGROUND: The UK Lung Cancer Screening (UKLS) trial is a randomised pilot trial of low-dose CT (LDCT) screening for individuals at high risk of lung cancer. We assessed the long-term psychosocial impact on individuals participating in the UKLS trial. METHODS: A random sample of individuals aged 50-75 years was contacted via primary care. High-risk individuals who completed T0 questionnaires (baseline) were randomised to LDCT screening (intervention) or usual care (no screening control). T1 questionnaires were sent 2 weeks after baseline scan results or control assignment. T2 questionnaires were sent up to 2 years after recruitment. Measures included cancer distress, anxiety, depression and decision satisfaction. RESULTS: A total of 4037 high-risk individuals were randomised and they completed T0 questionnaires (n=2018 intervention, n=2019 control). Cancer distress was higher at T1 in intervention arm participants who received positive screening results (p≤0.001), but not at T2 (p=0.04). T2 anxiety (p≤0.001) and depression (p≤0.01) were higher in the control arm, but the absolute differences were small and not clinically relevant. At both time points, fewer control than screened participants were satisfied with their decision to participate in UKLS (p≤0.001). Regardless of trial allocation, cancer distress was higher in women (p≤0.01), participants aged ≤65 years (p≤0.001), current smokers (p≤0.001), those with lung cancer experience (p≤0.001) and those recruited from the Liverpool area (p≤0.001). CONCLUSION: Lung cancer screening using LDCT appears to have no clinically significant long-term psychosocial impact on high-risk participants. Strategies for engaging and supporting underserved groups are the key to implement routine lung cancer screening in the UK. TRIAL REGISTRATION NUMBER: ISRCTN 78513845; results.