We describe the case of an 82-year-old female referred to the vascular clinic for further evaluation and management of suspected inferior vena cava (IVC) thrombosis. She had previously presented to the general practitioner with a one-week history of vague abdominal pain in the right and left loins. Contrast-enhanced magnetic resonance imaging (MRI) of the abdomen and magnetic resonance angiography/magnetic resonance venography (MRA/MRV) revealed a 10 cm filling defect in the IVC, with the inferior margin of ≈5.8 cm proximal to the aortic bifurcation and its superior margin in the intrahepatic portion of the IVC. The filling defect had a transverse diameter of 2.6 cm and displayed heterogenous enhancement with contrast.We performed an endovascular biopsy with fluoroscopy (anteroposterior {AP} and lateral views) being utilized throughout the procedure to locate the mass and position the forceps in the tumor bed. The IVC was accessed via the right common femoral vein with a 10F catheter sheath. The sheath was advanced using the Seldinger technique to within ≈1 cm of the mass; then, a biopsy forceps (Micro-Tech single-use 8.5 mm biopsy forceps, Nanjing, China) was inserted, and six tissue samples were obtained.We report this case to add to the growing evidence that endovascular biopsy of IVC tumors can be performed safely and effectively.