This paper describes a semi-automatic system for registering and visualizing CT (Computer Tomography) and MR (Magnetic Resonance) images the cervical spine. Registration requires identifying similar objects or structures in each image set. Identifying similar structures for this application is complicated because complementary imaging modalities are used. Following structure identification, the mapping transformation from one image set to the other can be determined using a non-linear optimization procedure. The final step is visualizing the results of the registered images sets.