Abstract: The evaluation of power flow in vibrational structure is treated theoretically, experimentally and by computer simulation. It is shown that the bending wave power can be measured with two transducers, as long as the error caused by near-field is known well. The method is very similar to the sound power measurement in air. The error caused by this way is calculated. Comparison between measurement and theory shows that in thin rods the bending wave power can be calculated with an accuracy of better than 2 dB. At low frequencies the limiting factor is the near-field influence, at high frequencies it is the transducer separation, the mass loading by the transducers and the phase difference, etc.