Methods of guiding magnetic particles in a controlled fashion through the arterial system in vivo using external magnetic fields are explored. Included are discussions of applications, magnetic field properties needed to allow guiding based on particle characteristics, hemodynamic forces, the uniformity of field and gradients, variable tissue characteristics, and imaging techniques employed to view these particles while in transport. These factors influence the type of magnetic guidance system that is needed for an effective drug delivery system. This thesis reviews past magnetic drug delivery work, variables, and concepts that needed to be understood for the development of an in vivo magnetic drug delivery system. The results of this thesis are the concise study and review of present methods for guided magnetic particles, aggregate theoretical work to allow proper hypotheses and extrapolations to be made, and experimental applications of these hypotheses to a working magnetic guidance system. The design and characterization of a magnetic guidance system was discussed and built. The restraint for this system that balanced multiple competing variables was primarily an active volume of 0.64 cm3, a workspace clearance of at least an inch on every side, a field of 0.3T, and a local axial gradient of 13 T/m. 3D electromagnetic finite element analysis modeling was performed and compared with experimental results. Drug delivery vehicles, a series of magnetic seeds, were successfully characterized using a vibrating sample magnetometer. Next, the magnetic seed was investigated under various flow conditions in vitro to analyze the effectiveness of the drug delivery system. Finally, the drug delivery system was successfully demonstrated under limiting assumptions of a specific magnetic field and gradient, seed material, a low fluid flow, and a small volume. / Master of Science