This work demonstrates the feasibility of using a superharmonic injection-locked oscillator as a power amplifier for short-range, low-power applications. This paper presents two fully integrated, differential superharmonic injection-locked power amplifiers (ILPA) operating at 433 MHz and 2.4 GHz. The two circuits were fabricated in a standard 0.18 μ m CMOS technology. Measurement results of the 2.4 GHz ILPA show a maximum gain of 31 dB from only one stage that occupies a chip area of only 0.6 mm2 with all components fully integrated. The ILPA delivers an output power of 7.6 dBm from a 1.5 V supply voltage with a power added efficiency of 36%.