An effective synthesis procedure is presented for the design of broadband microwave amplifiers using GaAs f.e.t.s. Based upon Youla's theory of matching, the equivalent input and output impedances of the GaAs f.e.t. are equalised to resistive source and load by lossless networks to achieve the nth order Cheby¿¿shev and Butterworth bandpass transducer power gain responses. The matching networks can also be designed to compensate for the gain rolloff of the GaAs f.e.t. which is approximately 6 dB/octave. The synthesis produces lumped lossless matching networks which can be approximated by distributed networks to a very good extent for 40% bandwidth or less. Examples are presented to illustrate the effectiveness of the synthesis procedure.