Stereotactic ultrasonography is a technique for determining the position and orientation of B-mode ultrasound images in a reference coordinate system. A technique for constructing three-dimensional (3D) image volumes has been developed that uses this new technology. Given several registered images, a 3D volume is constructed either by a "nearest-neighbor" or a "closest-points" interpolation approach. The resulting volume can be rendered using 3D rendering software. In addition, the voxels in the volume are at known positions allowing determination of position for structures in the volume. Results are shown for various test cases, and applicability to medical imaging applications and stereotactic neurosurgery is discussed.