Although many prognostic factors have been identified for lung cancers, new ones are needed to determine the course of the disease. Recently, a high neutrophil to lymphocyte ratio (NLR) prior to surgery or treatment has been shown to be an indicator of prognosis for cancer. The aim of this study was to investigate the value of NLR as a prognostic factor and the correlation between NLR and other probable clinical prognostic factors in non small cell lung cancer patients prior to treatment.