Steel Reinforced Concrete Structures have been adopted to railway constructions since the era of Japanese National Railway. On the other hand, the model code for design of Hybrid Structures including steel reinforced concrete structures has not yet been established. Meanwhile many types of Hybrid Structures, which make the most of merits of structural materials such as steel and concrete, are now developed in the civil engineering field and their application to railway constructions shows a tendency to dramatically spread. In this situation, Model Code for Design of Hybrid Railway Structures is newly drafted, adopting the limit state design method in all aspects. The model code consists of 3 sections of the general rule of Hybrid Structures, the design of steel reinforced concrete structures and of concrete filled tubular steel structures. In this paper, the key-points of the new code for design of Hybrid Structures are described. The new model code is expected to be made public by Japanese Ministry of Transport in 1998.