Objectives: According to 2018 United States and international lung cancer and pathology guidelines, testing of EGFR, ALK, ROS1 and BRAF genes is a minimum requirement to identify targeted therapy options in patients with advanced non-small cell lung cancer (aNSCLC). We describe real-world use and clinical features of next generation sequencing (NGS) and other non-NGS testing technologies in these patients. Materials and methods: Patients were from the Flatiron Health electronic health record-derived de-identified database and were newly diagnosed with non-squamous aNSCLC between 1 January 2018 and 30 June 2019. We describe occurrence and patterns of NGS-(including comprehensive genomic profiling [CGP]) and non-NGSbased genomic testing before the start of first-line therapy, unsuccessful genotyping (< 4 genes tested) and incidence of potentially missed targeted therapy options (< 4 genes tested with no positive results). Results: Among 3050 patients, 2356 received any type of genomic testing (NGS: 1406 [59.7%]). Unsuccessful genotyping occurred in 13.2% and 52.2% of NGS-and non-NGS-tested patients, respectively. Among NGS-tested patients, 10.0% had a potentially missed targeted therapy option (CGP: 2.9%), compared with 40.2% in the nonNGS tested group. While all four guideline-recommended genes were tested in & GE; 92% of patients who had NGS testing, when only non-NGS testing was used, although EGFR and ALK had similarly high testing proportions, BRAF and ROS1 (56.1% and 83.7%, respectively) were examined less often. Conclusions: Our findings suggest that in aNSCLC clinical practice, NGS testing may help to avoid potentially missed targeted therapy options and improve testing uptake for recently approved biomarkers. Results therefore support the use of guideline-recommended broad-panel NGS testing in clinical practice.