Various design loads used in the strength evaluation of ship structures have been introduced currently by classification societies. As most of such design loads have been determined as the standard loads for the sake of convenience, the relationships between the design loads and the sea states actually encountered by ships seem to be poor. Accordingly, it may be difficult to refer and utilize them as the fundamental design concepts for ship designers or the operational guidelines for ship operators. Under these circumstances, authors proposed the practical estimation methods of the design sea states, the design regular waves and the design loads having transparent and consistent backgrounds to the actual loads acting on primary structural members of tankers in the previous papers^1.2). In this paper, it is firstly confirmed that the proposed methods for tankers can also be applied in the primary structural members of bulk carriers. Furthermore, in order to improve the estimating accuracy of the design loads, the necessary modification is carried out considering the specific structural type and loading condition of bulk carrier. Finally, the comparison between the results obtained by the structural analysis of hold model applying the proposed design loads and long-term values of stresses directly obtained using the transfer function of structural response for different loading conditions are introduced and discussed in detail.