Objective: It is aimed to investigate the survival outcomes and prognostic factors after curative treatment of patients diagnosed with synchronous oligometastatic non-small cell lung carcinoma. Materials and Methods: Fifty-two patients from 3 centers diagnosed between 2014 and 2019 were analyzed. The treatment results of thoracic and oligometastatic regions were retrospectively evaluated. The Kaplan-Meier method was used to determine the overall survival (OS) and progression-free survival (PFS) and log-rank tests for the factors affecting survival. Cox regression analysis was employed for multivariate analysis. Results: Of the 52 patients, 46 (88%) had <2 organ involvement at diagnosis. Treatment of oligometastasis was radiotherapy (RT) in 37, surgery in 4, and surgery with RT in 11 patients. Median 60 Gy were administered to the thoracic tumor. Median RT dose for oligometastasis was 30 Gy in median 5 fractions with either stereotactic body radiation therapy or conventional RT. The median follow-up was 18 months. The median OS and PFS were 35 and 20 months, respectively. The 1-, 2-, and 3-year OS rates were 80.5%, 60.2%, and 41.2%, while the corresponding PFS rates were 75%, 42.5%, and 21.5%, respectively. Multivariate Cox regression analysis revealed that the Eastern Cooperative Oncology Group performance status of "0" and thoracic RT dose over 60 Gy were significant prognostic factors for both the OS and PFS. Conclusions: Definitive chemoradiotherapy to the thoracic tumor and treatment of oligometastasis region indicate promising survival outcomes.