OBJECTIVES: To examine patient characteristics, treatment patterns, and healthcare resource utilization of patients with neuroendocrine tumors (NETs) in the US. METHODS: Using a US administrative claims database, commercially-insured adults newly diagnosed with carcinoid tumors (ICD-9-CM: 209.xx) or pancreatic islet cell tumors (ICD-9-CM: 157.4 and 211.7) between 07/01/2007 and 12/31/2010 were identified (the date of the first observed diagnosis as the index date). Patients were required to have 6-month pre-index and 12-month post-index continuous enrollment. Descriptive analysis was performed to describe demographic and clinical characteristics, treatment patterns for NETs, and healthcare resource utilization during the 12-month post-index period. Similar analysis was conducted for Medicare-eligible individuals with the supplemental private insurance. RESULTS: This study included 3,940 commercially-insured individuals (mean age: 52.3 years; 55.4% female) and 1,658 Medicare-eligible individuals (mean age: 74.9 years; 49.0% female) with NETs. In the commercial population, carcinoid syndrome (33.2%), liver metastasis (22.4%), and nausea/vomiting (18.2%) were most common among the comorbidities evaluated. While 19.5% of individuals received surgical therapy and 17.5% received medical therapy (somatostatin analogue treatment) as the first-line treatment, nearly two-thirds received neither of those treatments. During the 12-month post-index period, about half of individuals had inpatient hospitalization and 35.4% had emergency room visits; the mean physician office visit was 19.9. In the Medicare population, carcinoid syndrome (27.4%), liver metastasis (20.7%), and diarrhea (16.1%) were the most prevalent comorbidities. While 13.2% received surgical therapy and 19.8% received medical therapy, over two-thirds received neither. Approximately half of individuals had inpatient hospitalization and 37.3% had emergency room visit during the 12-month post-index period; the mean physician office visit was 26.1. CONCLUSIONS: This exploratory study described real world treatment patterns of patients with NETs, and future research should investigate the management strategy of different symptoms in this population and its impact on healthcare resource utilization and costs.