K-band low-noise MMIC’s, based on pseudomorphic modulation doped FET’s (P-MODFET’s), have been developed. These dual stage MMIC’s incorporate P-MODFET’s, with 0.35 x 60-pm2 gates, as the active elements, e-beam-written tuning elements, and dc-blocking and bias networks. The dual-stage chips exhibited a maximum gain of 10.2 dB at 59.5 GHz and a minimum noise figure of 5.3 dB, with an associated gain of 8.2 dB at 58.2 GHz. Further, a cascaded four-stage amplifier (two MMIC modules) exhibited 5.8-dB minimum noise figure with an associated gain of 18.3 dB at 58 GHz and up to 21.1 dB of maximum gain. We believe that these are the first reported results for any pseudomorphic MODFET-based MMIC’s and that the minimum noise figures of 5.3 and 5.8 dB for our dual-stage and cascaded four-stage LNA’s, respectively, are the lowest currently reported for K-band MMIC’s.