We have constructed a life-sized fully three-dimensional (3D) rigid flow-through model of the cerebral vasculature. Average vessel diameters and lengths, taken from published values in the literature, were used to describe the geometry of our phantom; numerically controlled machining techniques were used to fabricate the model. Inflow to the phantom is provided through two internal carotid arteries and two vertebral arteries. Outflow is provided through the anterior cerebral arteries, the middle cerebral arteries, and the posterior cerebral arteries. The phantom includes the circle of Willis, and aneurysms of variable size may be attached at different locations. We have tested the model for geometric accuracy using high-resolution MR and CT imaging protocols, and have found that measured and prescribed diameters agree to within better than 4%. Flow dynamics, including waveform shape and flow division between branches, also mimic that seen in vivo, with flows within 16% (on average) of the prescribed values. We present 3D magnetic resonance angiography, digital subtraction angiography, and computed rotational angiography images of the phantom under conditions that mimic physiological situations.