Background/aim: The purpose of the study is to determine the cost-effectiveness of the chemotherapy medications that contain gemcitabine and pemetrexed, which are used in the treatment of advanced nonsmall cell lung cancer (NSCLC). Materials and methods: The study evaluated the effectiveness and cost of platinum-based pemetrexed and gemcitabine treatments as the first-line treatment of advanced NSCLC with the use of the Markov model, and from the perspective of the Social Security Institution. NSCLC costs calculated on the basis of experts' opinions and the effectiveness values calculated by administering the EQ-5D questionnaire to the patients were analyzed. All direct medical costs were included in the model. Results: While the life-long cost of gemcitabine/cisplatin treatment was determined to be 10,347.45 Turkish lira per patient, it was determined as 17,783.34 for pemetrexed/cisplatin treatment. The incremental cost of pemetrexed/cisplatin treatment is 220,754 per quality-adjusted life year. Conclusion: Although there is no official threshold value in Turkey, due to the fact that the incremental cost effectiveness ratio exceeds the threshold value calculated on the basis of GDP per capita, it is understood that pemetrexed/cisplatin is not cost-effective in the first-line treatment of advanced NSCLC.