In this paper, a 94 GHz flip-chip assembled CMOS amplifier with transition compensation is presented. Flip-chip process with a bump size (30 μm × 30 μm × 27 μm) is developed for millimeter-wave applications. Without the flip-chip transition compensation, the frequencies of the best return losses of the amplifier shifts to 82-85 GHz, which deviate from the bare die measurement results of 96 GHz. By applying the compensation network in the transition, the dips of the return loss become much closer to the bare die measurement results. To the best of our knowledge, this is the first demonstration of a CMOS amplifier with flip-chip connection in millimeter-wave frequencies.