INTRODUCTION: Although neuroradiological techniques have expanded, stereotactic needle biopsy is a simple, ubiquitous,and immediate strategy for established or potential brain tumor patients with atypical clinical and/or radiographic findings. METHODS: Outpatient stereotactic needle biopsies performed by a single surgeon from August 2020 through November 2022 were retrospectively reviewed. Electronic medical records were queried for clinical, perioperative, and tumor demographics. Financial records were queried for insurance and payment reports. Descriptive statistics were used to characterize comparisons among collected variables. RESULTS: 107 consecutive stereotactic needle biopsy procedures were conducted in adult brain tumor patients. All biopsies were performed using a single needle-pass in the outpatient setting, targeting supratentorial lesions in 89.7% of cases. Tissue diagnosis was established in 96% of procedures, with glioma being the most common histology. No intraoperative or perioperative complications occurred. Four patients (3.7%) were admitted overnight due to urinary retention (n = 2) and asymptomatic tract hemorrhage (n = 2), respectively. Insurance approval was sought preoperatively from non-commercial (31.7%) and commercial (68.3%) payors and approved in all cases. Postoperatively, 30.8% of patients received an experimental therapeutic on the basis of tissue analysis. CONCLUSIONS: We report the largest experience to date with outpatient stereotactic needle biopsy in newly-diagnosed and recurrent brain tumor patients. Our findings identify this strategy as a cost-effective alternative to advanced imaging that facilitates clinical trial accrual through tissue acquisition.