Abstract: The present invention relates to an implantable medical device that is used to deliver drugs or other therapeutic agents into a patient. More specifically, the present invention is for a drug infusion device which features a bulkhead having integrated subsystems. The bulkhead is the main structural component of the implantable medical device. The integrated bulkhead of the present invention has all or portions of subassemblies, such as a pump, motor and gear train, electronics, drug fill port, catheter access port, fluid pathways, filter and overpressure mechanism, built into the bulkhead. Integrating the subsystems of the bulkhead simplifies the assembly process and reduces the overall cost of manufacture by reducing the number of components to assemble and reducing the number of manufacturing steps. Additionally, integrating the subassemblies into the bulkhead allows for increased accuracy in controlling the connections between the subsystems, which allows for improved delivery of drugs to the patient.