OBJECTIVES: Lung cancer is the common cause of cancer death in developing countries. In Thailand, lung cancer, including non-small cell lung cancer (NSCLC) ranks third of 10 leading sites of cancers. NSCLC has a poor prognosis which has an effect on quality of life of both individual patients and their family. Understanding the quality of life and health utility for lung cancer is important; however, little data are available in Thailand. This study aimed to measure baseline health utility among advance NSCLC patients before treated with first-line chemotherapy. METHODS: A prospective cohort study was implemented in Maharaj Nakorn Chiang Mai hospital which is a medical teaching hospital located in the north of Thailand. A variety of first-line chemotherapy regimens were available for treatment. In this study, we included patients aged 18 or above, diagnosed with NSCLC with stage IIIB and IV, had performance status (ECOG) 0-1, and were scheduled to receive first-line chemotherapy. The data were collected from January to March 2012. Utility was measured using EuroQoL Thai version. The data were collected while patients visited outpatient oncology clinic. Descriptive statistics were used for data analyses. RESULTS: During three months period, 24 patients were included. Eight patients were NSCLC stage IIIB while 16 were stage IV. Mean utility value of overall NSCLC, NSCLC stage IIIB and NSCLC stage IV at baseline before receiving first-line chemotherapy were 0.419, 0.473 and 0.392, respectively. CONCLUSIONS: Utility values of patients with advanced NSCLC are likely to be downward due to the severity of disease; therefore, choosing the appropriate first-line chemotherapy regimen might need to consider the quality of life of patients.