We assessed whether single nucleotide polymorphisms (SNPs) in MDR1 gene C3435T predicted the outcome of platinum-based chemotherapies and survival in our non small cell lung cancer (NSCLC) patients. A total of 79 non-small cell lung cancer patients were enrolled to study. We determined the MDR1 C3435T single nucleotide gene polymorphisms. Median age was 60 years: 91.7% male, 8.9% female. We found that CC, CT, TT genotype and T, C allele frequencies in lung cancer patients as 24.1%, 62%, 13.9% and 44.3%, 55.7%, respectively. Patients with CT genotype had a higher response rate (11.4%) than the other genotypes. However, this difference is not statistically significant (p = 0.743). Cox regression analysis for overall survival showed that ECOG PS status 0 (HR PS 1 vs. 0, 5.68 p = 0.002; HR of PS 2 vs. 0 is 21.579, p = 0.001; HR of PS 3 vs. 0 is 35.35, p = 0.001), stage <= II (HR of stage III vs. I+II is 17.77; p = 0.016, HR of stage IV vs. I+II is 26.97, p=0.006), and albumin level >= 3 g/dl (HR of albumin <3 g/dl vs. >= 3 g/dl is 2.46, p = 0.044) were the most important prognostic factors (also, time to progression was related to these factors). There was no significant association between the genotypes and clinicopathologic parameters; however, good performance status, early stage and >= 3 g/dl albumin level were found to be the most important prognostic factors for overall survival and progression-free survival. (C) 2012 Elsevier B.V. All rights reserved.