Iliac vein compression syndrome (IVCS), also known as May-Thurner syndrome, is the result of compression of the left common iliac vein between the right common iliac artery and overlying vertebrae. The most common clinical presentation is left lower extremity deep vein thrombosis. Rarely, a patient with IVCS can present with obstruction of venous outflow, without deep vein thrombosis. Iliac vein compression, with or without thrombosis, should be treated if symptomatic. We present a patient with IVCS that was initially diagnosed with transabdominal ultrasonography (US), and then confirmed with computed tomography and venography with pressure measurements. We believe this is the first report of an IVCS patient diagnosed with US.