The aim of the study was to determine survival benefit of the microwave ablation (MWA)/chemotherapy combination compared with chemotherapy alone. Patients with untreated, stage IIIB or IV NSCLC and at least one additional measurable site other than the ablative site were enrolled. They were divided into MWA/chemotherapy group and chemotherapy group. The primary endpoint was progression-free survival (PFS); secondary endpoints included response, time to local progression (TTLP), overall survival (OS), and adverse events (AEs). Forty-six and twenty-eight patients were enrolled in the MWA/chemotherapy group and chemotherapy group, respectively. Complete ablation was observed in 84.8 % patients in the MWA/chemotherapy group. Median TTLP was 27.0 months. Objective response rate and disease control rate in MWA/chemotherapy group were 21.7 and 76.1 %, and in the chemotherapy group were 32.1 % (p = 0.320) and 75.0 % (p = 0.916), respectively. MWA/chemotherapy combination prolonged PFS [MWA/chemotherapy group 10.9 (95 % CI 5.1-16.7) ms vs. chemotherapy group 4.8 (95 % CI 3.9-5.8) ms, p = 0.001] and tended to improve OS [MWA/chemotherapy group 23.9 (95 % CI 15.2-32.6) ms vs. chemotherapy group 17.3 (95 % CI 15.2-19.3) ms, p = 0.140]. Multivariate analyses showed that MWA was an independent prognostic factor of PFS and primary tumor size was an independent prognostic factor of OS. AEs of MWA were observed in 67.4 % patients. Chemotherapy-associated AEs were observed in 39.1 and 53.6 % of patients in the MWA/chemotherapy and chemotherapy group, respectively. MWA/chemotherapy combination improved PFS of advanced NSCLC compared to chemotherapy alone, and the combination did not increase the adverse events of chemotherapy.