Deep venous thrombosis (DVT) involving the upper extremities, chest, and neck has become appreciated as a significant cause of morbidity, especially in individuals with central venous access devices (CVAD). Like DVT involving the leg and pelvic veins, axillo-subclavian vein thrombosis can result in pulmonary embolism, post-thrombotic syndrome, and venous limb gangrene. Data relating to the natural history of internal jugular vein thrombosis (IJVT) is lacking. Risk factors, treatment patterns, and clinically relevant outcomes were retrospectively assessed in 74 consecutive patients with isolated IJVT. All patients (median age 66 years; range 36-80) had CVAD-associated IJVT, 22 (29.7%) had a history of cancer, and 14 (18.9%) had a history of prior DVT. Thirty-two (43.2%) were treated with systemic anticoagulation, 2 (2.7%) received a superior vena cava filter, and 40 (54.1%) received no specific therapy. Of the patients who underwent serial imaging, 7/40 (17.5%) had thrombus propagation. Two (2.7%) patients were diagnosed with pulmonary embolism, 8 (10.8%) were diagnosed with malignancy during a median follow-up of 20 months (range 18-24), and 3/53 (5.7%) suffered a recurrent DVT. Outcomes similar to those seen in leg DVT were observed. The most effective treatment strategy remains to be determined, but anticoagulant treatment was associated with a trend towards reduced all-cause mortality.