In this report, the authors present a case of segmental thrombosis of left subclavian vein that was inaccessible to conventional venography and inconclusive in magnetic resonance techniques (spin echo, gradient echo) but was clearly demonstrated by two-dimensional time-of-flight magnetic resonance angiography (2D TOF MRA). This technique is very sensitive to detect slow flow or partial occlusion of the vessels and is of great help in solving the problem of axillary-subclavian venous obstruction or thrombophlebitis.