A recently proposed approach for the prediction of power amplifier (PA) intermodulation distortion (IMD) on the hasis of single-tone Harmonic Balance simulations is used in this paper for the definition of a numerically efficient design procedure of highly linear microwave power amplifiers. In particular, it is shown how standard design goals on third or fifth order intermodulation products, usually involving timeconsuming two-tone HB analyses, are more simply hut with sufficient accuracy taken into account by means of faster single-tone HB analyses in the iterative design process. The proposed procedure is compared with standard approaches in the design case of single-transistor and multiple paralleled-transistors MMlC amplifiers, showing dramatic reductions in computation time.