Despite all efforts at management, prognosis of advanced lung cancer is extremely poor, with a median survival time of similar to 1 year. The number of cancer patients aged >70 years is significantly increased among the cancer patient population. The aim of this study was to investigate the clinical importance of age in lung cancer. Data from 110 patients with histologically confirmed lung cancer, who were treated and followed up in the Institute of Oncology, University of Istanbul, were recorded from medical charts. There were 100 (91%) males with a median age of 59 years (range, 35-88 years). The majority of patients had non-small cell lung cancer (NSCLC; 84%) and metastatic stage (56%). The rate of positive response to chemotherapy was lower in elderly patients (P=0.01) and the incidence of anemia was higher compared with that in younger patients (P=0.02). The majority of mortalities occurred in elderly patients (P=0.01). The median survival time of elderly patients was significantly lower compared with that of younger patients (37.8 vs. 57 weeks; P=0.009). The 1-year survival rates in younger and elderly patients were 67.3 and 42.5%, respectively. In multivariate analysis, elderly patients also had significantly poorer survival (P=0.023). In the group of elderly patients, analyses revealed that significant prognostic factors, including stage of disease and serum lactate dehydrogenase (LDH) levels, were associated with survival. Elderly patients diagnosed with small cell lung cancer had a poorer outcome compared with those with NSCLC (P=0.009), and older patients with elevated serum LDH levels had a shorter survival time compared with those with normal levels (P=0.042). In conclusion, age is one of the major prognostic factors affecting survival in lung cancer patients; therefore, patients should be managed according to age in clinical practice.