409 Background: Cytoreductive surgery (CRS – gastrectomy combined with metastasectomy) for non-palliative indications is controversial for patients with metastatic gastric adenocarcinoma (MGA). We hypothesized that CRS in addition to systemic chemotherapy is associated with an improved survival when compared to patients with MGA receiving chemotherapy alone. Methods: Patients with MGA who received systemic chemotherapy between 2004-2016 were identified using the National Cancer Database (NCDB). Nearest neighbor 1:1 propensity score matching of demographic, tumor-related and treatment-related factors was used to create comparable groups. Overall survival (OS) was compared between subgroups using Kaplan-Meier analyses. Immortal bias analysis was performed among those that survived at least 90 days. Results: We identified 29,728 chemotherapy-treated patients who were divided into 4 subgroups: No surgery (NS, n = 25,690), metastasectomy alone (n = 1170), gastrectomy alone (n = 2248) and CRS (n = 620) with a median OS of 8.6, 10.9, 14.8 and 16.3 months, respectively (p < 0.001). Compared to patients who underwent no surgery, patients who underwent CRS were younger (58.9±13.4 vs. 62.0±13.1 years), had lower proportion of disease involving multiple sites (5.0% vs. 26.2%), and were more likely to have clinically occult disease (cM0 58.9% vs. 7.3%) - all p < 0.001. OS for propensity matched patients who underwent CRS (n = 490) was longer than NS (16.3 vs. 8.8 months, p < 0.001), including those with clinical M1 stage (n = 203) in both unmatched and propensity matched (median OS 19.7 vs. 8.6 months, p < 0.001) cohorts. On Cox regression model using the matched data, the hazard ratio for CRS vs. NS was 0.80 (95%CI 0.76-0.84). In the immortal matched cohort, the corresponding median OS was 16.7 vs. 9.7 months, p < 0.001. Conclusions: CRS in addition to systemic chemotherapy may be associated with an OS benefit in a selected group of patients with metastatic gastric adenocarcinoma. Suboptimal matching for tumor burden is our major limitation. In contrast to studies that focus on gastrectomy alone in the setting of MGA, this study highlights the role of CRS among patients receiving systemic chemotherapy.