Objective. Although data accumulated in clinical trials have higher accuracy compared to real-world data and are irreplaceably valuable, most previous clinical trial data have been left unutilized. Methods. The Japan Lung Cancer Society (JLCS) asked six clinical trial groups that conducted randomized clinical trials on curative chemoradiation for locally advanced non-small cell lung cancer (NSCLC) to provide data. After obtaining consent from all six groups, data were collected from August 2019 to June 2021. Results. Eight trials, JCOG9812, JCOG0301, NJLCG0601, OLCSG0007, WJTOG0105, WJOG5008L, SPECTRA, and TORG1018, were included. More than 3000 data items were integrated into 408 items by adjusting their definitions and units. The total number of collected cases was 1288: median age (range), 66 (30-93) years; sex (male/female) 1064/224; histological type (squamous cell carcinoma/adenocarcinoma/other NSCLC/unknown) 517/629/138/4; and stage IIIA/B, 536/752. The median overall survival was 24.6 months, with 2-, 5-, and 10-year survival rates of 51.1%, 22.5%, and 13.8%, respectively, in all enrollments. The median progression-free survival (PFS) was 9.5 months, with 2-, 5-, and 10-year PFS rates of 22.4%, 13.0%, and 9.1%, respectively. Part of the information in the database has been made available on the JLCS web page, and the JLCS members were provided the right to propose research using the database. Conclusion. The integration and sharing of clinical trial data for research purposes was made real by the non-profit, academic organization, the JLCS. This database will lead to innovative researches and contribute to the improvement of lung cancer treatment and future research.