In this paper the resistance of a floating body in a uniform stream of a viscous fluid is obtained theoretically to Oseen's approximation. It is shown that the total resistance is expressed as the sum of two components, namely the wave making resistance and the viscous resistance. The former is determined by the source and Oseenlet distributed over the hull surface, while the latter is proportional to the total strength of the Oseenlet. The effect of the Oseenlet on the waves and the pressure is turned out to be the same as that of the source. The authors tried to apply these results to the actual ship resistance problem, and found that there exists a new component of the wave making resistance which is proportional to the skin friction coefficient C_f .