Although the results of studies in populations with low selenium status indicate an inverse correlation between body selenium levels and the risk of the lung cancer, the effect of this microelement on survival has not been studied.We performed a prospective study of 302 patients diagnosed with lung cancer in Szczecin, Poland. Selenium concentration in serum was measured at the time of diagnosis and before treatment. All patients were followed for a maximum of 80 months or until death. Vital status was obtained from the Polish National Death Registry.Using Cox proportional hazard analysis, performed for all individuals with lung cancer, the hazard ratio (HR) for death from all causes was 1.25 (95% CI: 0.86-1.83, P = 0.99) for patients in the lowest tertile compared to those in the highest tertile of serum selenium levels. Among the patients with stage I disease this relationship was significant (HR-2.73; P = 0.01) for selenium level in tertile 1 (<57 μg/L) compared to tertile 3 (>69 μg/L, reference). The 80 months crude survival after diagnosis was 79.5% (95% CI: 68.5-92.4%) for individuals in the highest tertile and 58.1% (95% CI: 45.1-74.9%) for individuals in the lowest tertile with stage I lung cancer.These results suggest that in patients undergoing treatment for stage I lung cancer, serum selenium levels at the time of diagnosis (>69 μg/L) may be associated with improved overall survival.