Over the past several years the Mitsui Ship-building & Engineering Co., Ltd. has been engaged in the development of a new hull form applying the theory of wave-making resistance. This procedure is well known as “Waveless Hull Form Theory” developed by Prof. Inui. This paper refers to the practical cases of the applications of the Theory through several experimental works. It should seem that the results of experiments suggested a few questions how to apply the Theory. The most important ones are the followings : (1) Applying the Theory to designs of Bulbous Bow is to be the most efficient. But the position, size and shape of “bulb” must be selected carefully through experiments. (2) Reffering to the “Minimum Wave-Making Resistance Theory” the results of experiments have not necessarily shown a satisfactory agreements with the Theory. One reason will lie in the nonlinear effects not explained by the Theory The authors believe the more investigations must be continued both in theory and experiment, especially in case of large tanker hulls.