612 Background: The aim of this study was to examine the impact of diabetes mellitus (DM) on survival in neuroendocrine tumor and the impact of neuroendocrine tumor on glycemic control in DM. Methods: Patients with newly diagnosed neuroendocrine tumor with and without DM were matched 1:1 according to age, gender, and year of cancer diagnosis (2005-2017). The file was linked to the electronic medical record to obtain information on DM and neuroendocrine tumor therapies and laboratory results. There were 59 matched pairs (total 118 patients) included in the analysis. We compared characteristics between cases and controls and assessed survival with the Kaplan-Meier method and Cox proportional hazards model. Mixed models compared hemoglobin A1c and glucose levels over time. Results: Median age of patients at diagnosis was 67 (40-86); 41% had stage IV disease. Women constituted 49% of the study population; 22% had pancreatic neuroendocrine tumor and 45% had another GI primary neuroendocrine tumor. No differences in race/ethnicity, marital status, alcohol or tobacco use were detected between cancer patients with and without DM. Mean BMI was significantly different between DM and non-DM patients (31.0 [7.90] versus 26.4 [5.27]); p = 0.011. Among those with DM, mean HbA1c during the year following cancer diagnosis was 7.3%. Mean glucose was significantly different between DM (159.1 [43.5] versus non-DM pts 117 [31.5]); p < 0.001. Median follow-up time was 32.8 (2.4-165.4) months in alive patients. Three year survival was estimated at 72% (95% CI: 60-86%) for DM patients versus 80% (95% CI: 70-92%) in non-DM patients by Kaplan Meier method (p = 0.82 log rank test). Hazard ratio (stratification for matched pairs) = 1.33 (95% CI: 0.56 – 3.16; p = 0.51). Conclusions: DM did not adversely impact survival in patients with neuroendocrine tumor. Neuroendocrine tumor and its treatment did not affect glycemic control. This should be reassuring to oncologists and endocrinologists who treat patients with neuroendocrine tumors and diabetes.