In this study, various limit states for vertical steel pipe piles of an open-type wharf are defined, then partial factors of design formulae are provisionally calculated based on reliability theory. Existing open-type wharves are targeted, and limit states for the ground bearing capacity and bending moment of the piles are examined. Considering the uncertainties of basic variables such as the coefficient of lateral subgrade reaction, the yield stress of the steel pipe piles and the ultimate shaft and tip resistances of piles, the reliability of existing structures that were designed using the current standard is evaluated using the advanced first-order second-moment method, and a set of partial factors is estimated based on the sensitivities of basic variables. Finally, the reliability index in the design section is calculated by the partial factor method, and the validity of the proposed technique is verified. Copyright ASCE 2006.