Venous thoracic outlet syndrome is a complex but rare disease that often can have excellent outcomes if quickly recognized and treated. The syndrome results from compression of the subclavian vein along its exit from the thoracic cavity and frequently affects young otherwise healthy patients. Modern diagnosis is made with a combination of clinical exam, appropriate non-invasive imaging, and, finally, contrast venography, which can be both diagnostic and therapeutic. Treatments have evolved over time to the point where patients can undergo less extensive procedures than previously performed and still maintain excellent outcomes. One of the most important predictors of outcome is the initiation of treatment within 14 days of symptoms. Hence, the importance of the accurate and prompt diagnosis of this syndrome in patients with an upper-extremity deep vein thrombotic episode cannot be further underscored. This review is a concise summary of the background and treatment algorithm for this patient population.