The Roadmap has been developed as a guide to the R&D and Code development tasks that could be considered in developing rules for High Temperature Gas-Cooled Reactors (HTGR). The primary focus of the Roadmap is on the development of a complete set of rules for the design and operating conditions that are being proposed for the Next Generation Nuclear Plant (NGNP). The near-term, Part I activities focus on development of ASME III, Division 5 Code rules based on the existing ASME II, Division 1, Subsection NH rules and existing Code Cases. The Phase I activities also include incorporation of the new graphite rules in Division 5. Intermediate term activities are also covered in the Roadmap in Phase II. The intermediate term activities focus on higher temperature service and advanced design methods applicable to future HTGR designs. Very long term activities, such as the development of risk-based or system-based code rules for the HTGR are not covered in this Roadmap.