OBJECTIVE : Aim of this study was to elucidate an alteration of quality of life (QOL) score before and after video-assisted thoracoscopic surgery (VATS) for non-small cell lung cancer (NSCLC) patients using the 5-level EuroQol-5D questionnaire (EQ-5D-5L). We also investigated how the preoperative QOL scores affected the postoperative clinical outcome prospectively. METHODS : Between July 2018 and December 2018, 24 consecutive NSCLC patients who underwent VATS were recruited. The EQ-5D-5L for Japanese was used with face-to-face interviews to estimate the utility values of QOL. RESULTS : QOL scores were significantly declined after surgery (0.81 ± 0.19 vs. 0.74 ± 0.11: P = 0.049). The levels of EQ-5D-5L questionnaire were not significantly different before and after surgery except Q4 (pain control). The levels of Q4 were significantly worsened after surgery (1.33 ± 0.56 vs. 1.88 ± 0.61, P < 0.001). Operation time and bleeding in the preoperative low-QOL score group (N = 13) was longer (215.4 ± 52.3 min. vs. 173.5 ± 42.3 min., respectively: P = 0.045) and more (116.2 ± 152.7 ml vs. 22.7 ± 20.1 ml, respectively: P = 0.049) than those in the high-QOL score group (N = 11). CONCLUSIONS : QOL survey for lung cancer patients using EQ-5D-5L is simple and useful to identify the issue facing at the medical team. Preoperative low QOL score could be a predicting factor for the longer operation time and more bleeding.