In this study, we undertook a randomized phase III trial of 105 NSCLC patients with oligo (one to four) -brain metastases. Patients were randomly assigned (1:1) to receive either stereotactic radiosurgery (SRS) followed by chemotherapy or upfront chemotherapy alone. The results demonstrated that SRS followed by chemotherapy did not improve overall survival compared with upfront chemotherapy only. It is unclear whether treating brain metastasis before starting systemic chemotherapy can improve survival compared with upfront chemotherapy in non-small-cell lung cancer (NSCLC) with asymptomatic cerebral oligo-metastases. We undertook a randomized, controlled trial of 105 patients with one to four brain metastases, admitted to Samsung Medical Center between 2008 and 2013. Patients were randomly assigned to receive stereotactic radiosurgery (SRS) (49 patients) followed by chemotherapy or upfront chemotherapy (49 patients). The primary end point was overall survival (OS) and secondary end points included central nervous system (CNS) progression-free survival, progression to symptomatic brain metastasis and brain functional outcome. The median age was 58 years (range, 29–85) with ECOG 0–1 performance status, and 40% of patients were never smokers. Most patients had adenocarcinoma, and about half of patients had only one brain metastasis, while the rest had multiple cerebral metastases. The median OS time was 14.6 months 95% confidence interval (CI), 9.2–20.0 in the SRS group and 15.3 months (95% CI, 7.2–23.4) for the upfront chemotherapy group (P = 0.418). There was no significant difference in time to CNS disease progression median, 9.4 months (SRS) versus 6.6 months (upfront chemotherapy),P = 0.248. Symptomatic progression of brain metastases was observed more frequently in the upfront chemotherapy group (26.5%) than the SRS group (18.4%) but without statistical significance. Although this study included smaller sample size than initially anticipated due to early termination, SRS followed by chemotherapy did not improve OS in oligo-brain metastases NSCLC patients compared with upfront chemotherapy. Further study with large number of patients should be needed to confirm the use of upfront chemotherapy alone in this subgroup of patients. NCT01301560.