Background: The proliferation of next-generation sequencing (NGS) tests provides an opportunity to advance oncology care. However, there are limited data about when and how NGS tests are used and the extent to which test results inform clinical care. Methods: Between February and May 2017, a survey developed by the National Cancer Institute and American Cancer Society was mailed to a nationally-representative sample of oncologists; 1281 responded, reflecting a 38% participation rate. Oncologists reported their use of NGS tests over the past year, including their use in different clinical scenarios. We restricted our analysis to the 1123 respondents who treated patients with solid tumors. Weighted percentages were used to describe NGS test use and its association with oncologists’ demographic and practice characteristics. Results: Overall, 63% of oncologists reported using NGS tests to guide treatment decisions. Among these oncologists, 36% used them “often” to guide treatment decisions for patients with advanced refractory disease, 29% to determine eligibility for clinical trials and 19% to decide whether to use FDA-approved drugs off-label. For 28% of oncologists, NGS test results informed treatment recommendations “often,” 53% reported “sometimes,” and 19% of oncologists reported that results “never” or “rarely” informed treatment recommendations. Oncologists < 50 years of age, practicing in an urban or suburban setting, treating patients at an academic center, holding a faculty appointment or receiving genomics training were more likely to use NGS tests. Over 50% of all oncologists reported that one or more patients presented with NGS test results from a commercially-available company they had not ordered. Conclusions: Most U.S. oncologists use NGS tests for their patients with solid tumors to inform treatment options for those with advanced cancer, and to identify clinical trials and/or approved drugs for off-label use. Among oncologist using NGS tests, over 80% reported that results informed their treatment recommendations either sometimes or often. Research is needed to more clearly establish the clinical utility of NGS tests and to inform clinical guidelines for their use in practice.