It has been suggested that the wave making resistance of a submerged body is reduced by downward lifting force. In the present study, it is focused to make more clear the characteristics of resistance of three-dimensional rectangular hydrofoils which generate downward lifting force. Measurements of drag and lifting force are carried out together with numerical simulations. The boundary element method is used for the simulation where an attached wake and the nonlinear free-surface conditions are invoked. The study is carried out by decomposing the total pressure resistance into the wave making resistance and the induced resistance components. The former is determined by the wave pattern analysis method for the computed wave patterns while the latter is by the subtraction of the wave making resistance component from the total resistance. The numerical simulations, which have been validated in the beginning compared with the measured, show that the wave making resistance is reduced by the downward lifting force. It is also made clear that the wave making resistance has a minimal value of almost zero at a certain lifting force which can be related to the buoyancy force. Effects of the submergence depth, Froude number and the volume and the aspect ratio of the hydrofoil are discussed.