A monolithic DC-70-GHz distributed amplifier (DA) using a 90-nm CMOS process is presented in this paper. The DA is composed of a cascaded single-stage distributed amplifier (CSSDA) and a conventional distributed amplifier (CDA). The CSSDA is adopted as the first-stage to increase the small-signal gain of the DA. The CDA is adopted as the second-stage for the higher output power. Moreover, the modified m-derived network and inductive peaking technique are adopted to further extend the gain and bandwidth of the DA. The measured average small-signal gain is 13 dB with a small-signal bandwidth from DC to 70 GHz. The measured maximum output 1-dB compression point (OP1dB) is 1 dBm. The chip size of the proposed DA is 0.99 × 0.79 mm2.