A new method of the design of tuned power oscillators, based on the method of the equivalent two-terminal networks, is presented. By the use of the proposed method, a phase shift of the feedback network can be taken into account and the phase condition for oscillation can be fulfilled at the resonant frequency of the output matching network. Hence, it is possible to obtain the output power and the collector efficiency of the oscillator as high as in the corresponding tuned power amplifier. An example of the design of the class C tuned power oscillator is also given. The proposed method is particularly important for the design of tuned power oscillators operating at high frequencies, when the phase shift introduced by the transistor is significant.