Background: Recurrences of non-small cell lung cancer (NSCLC) after surgery remain common and are associated with significant morbidity and mortality. Loco-regional or metastatic disease recurrence can lead to a substantial health care resource use and economic burden. The aim of this study was to estimate the effect of treating patients with early-stage NSCLC with adjuvant atezolizumab (ATZ) on the number of recurrences and direct healthcare costs in Germany, Spain, France Italy and the UK, together referred to as EU5. Methods: Using an epidemiological model, we estimated the reduction in loco-regional (LR) recurrences or distant metastases (DM) after adjuvant ATZ treatment following chemotherapy in operable NSCLC patients with PDL-1 expression of ≥ 50% on tumor cells (PD-L1 high), stage II-IIIA (AJCC 7^th edition staging), without EFGR or ALK alterations. We used data from cancer registries, published literature sources, and market research to obtain incidence rates, staging distribution, biomarker status data, and adjuvant treatment rates. Moreover, we used evidence on the disease-free survival (DFS) of patients on adjuvant ATZ from the IMpower010 (NCT02486718) clinical trial to calculate the projected reduction in the number of LR recurrences or DM over a 10-year period post-ATZ launch relative to best supportive care (BSC). The model considers the costs associated with treatment, management of adverse events, monitoring of the disease, and follow-up healthcare. Results: We project that between 2023 and 2033, 20,483 patients with resected PD-L1 high stage II-IIIA NSCLC would experience recurrence (LR, or DM, or both) in the EU5 if they were treated with BSC (adjuvant platinum-based chemotherapy) alone (Table 1). Assuming peak ATZ uptake of 75%, the model estimates that following adjuvant ATZ and chemotherapy, a total of 4,665 recurrences would be prevented in this patient population in the EU5 over 10 years, representing a 23% decrease in recurrence relative to BSC. These avoided recurrences in EU5 could translate into a considerable reduction in direct healthcare costs. Conclusions: Adjuvant ATZ following chemotherapy results in a considerable population-level reduction of loco-regional recurrence or distant metastasis in resected PD-L1 high stage II-IIIA NSCLC patients. This could translate into a substantial decrease in the economic and societal burden caused by the disease.