OBJECTIVES: To estimate the cost-effectiveness of maintenance therapy with oral erlotinib (150mg/day) and BSC compared with BSC, in patients with advanced non-small-cell lung cancer (NSCLC) EGFR WT and stable disease after completing four cycles of first-line platinum-based chemotherapy. METHODS: A Markov model including three health states (progression free survival, progression and death) was developed to evaluate the cost per life year gained (LYG) of maintenance treatment with erlotinib vs BSC from the Spanish National Healthcare System perspective. Clinical data inputs were based on the SATURN trial results. Resource utilization related to each health state was estimated by a Spanish Expert Panel. Drug and unitary costs were obtained from a Spanish database (€, 2012). The annual discount rate applied was 3.0% for cost and outcomes. The simulation was carried out over a 5 year time horizon and one-way deterministic and probabilistic sensitivity analyses were conducted to assess the uncertainty around key input values. RESULTS: In the prespecified subset of patients with EGFR WT and stable disease, the annual cost per patient of erlotinib and placebo, including supportive care and adverse events costs, was 23,912€ and 13,969€, respectively. Erlotinib also achieved a mean gain of 1.40 life-years compared with the 1.12 LYG with placebo. The incremental cost-effectiveness ratio of erlotinib relative to placebo was calculated to be 35,265 € per LYG. Sensitivity analyses confirmed the robustness of the results. CONCLUSIONS: In patients with advanced NSCLC EGFR WT and stable disease after 4 cycles of chemotherapy, maintenance treatment with erlotinib is a therapeutic option that increases survival of patients and may be cost-effective vs BSC in Spain.