Abstract Manufacturing design has been developed by Hyundai Heavy Industries Co., Ltd. (HHI) and Korea Domestic Agency (KODA) to manufacture real product. As the first step of development of the manufacturing design, fabrication feasibility study was carried out in accordance with the RCC-MR 2007. Fabrication sequence was drafted and engineering analyses have been performed to guarantee structural integrity of manufacturing design and to minimize welding distortion. Several design modification proposals were derived during fabrication feasibility study. Fabrication sequence and manufacturing techniques have been established based on the results of a fabrication feasibility study. 3D multi-part model was developed based on the reference multi-body model and manufacturing drawings have been produced. A full scale mock-up of the lower port stub extension (PSE) has been fabricated in order to verify weldability, applicability of non-destructive examination (NDE) and welding distortion. Several qualifications were also conducted to confirm that the manufacturing design satisfies the requirements for bending, solution heat treatment, welding and NDE. Manufacturing and inspection plans (MIP) have been prepared to start real fabrication. In this paper, manufacturing design procedure and major technical results of manufacturing design development are presented for ITER VV lower port.