The aim of this study was to analyze survival dependence on 3-D conformal radiotherapy dose applied to non-small cell lung cancer patients treated in Kaunas University of Medicine Hospital from year 1999 to 2001. One hundred fifteen patients with median age 67.3 years were analyzed. There were 101 men and 14 women. Squamous cell carcinoma was the most common type of histology (80.86% patients). Most patients (61.7%) had locally advanced lung cancer (stage III). Radiotherapy doses applied ranged from 30 Gy (3.0 Gy/10 fractions) to 70 Gy (2.0 Gy/35 fractions). After analysis of radiotherapy dose influence on survival statistically significant improvement in median survival with higher doses was found (p=0.0001 Breslow). The group of patients irradiated with higher than 50 Gy dose demonstrated better survival than patients treated with smaller doses. (Log rank p=0.0061, Breslow p=0.0013). There was a correlation between dose and conformity of dose distribution.