We describe a subaortic left brachiocephalic vein, a congenital anomaly that can be suspected during the rapid central vein assessment before central venous catheterization. Since the vein descends vertically/obliquely rapidly from its origin, we suggest that the puncture should be made at a greater angle (50°–60°) than what is usually used to puncture this vein (20°–30°). Failure to identify this anomaly may cause a failed puncture or complications from the puncture of adjacent blood vessels.