In this paper, an IQ oscillator/mixer circuit is presented in which the mixers are an integral part of the oscillator. The oscillator alone has accurate quadrature outputs, even in the presence of component mismatch. This precise quadrature is preserved when mixers are incorporated in the oscillator. An oscillator/mixer core for a carrier frequency of 5 GHz, suitable for a low-IF front-end, was designed and tested. The power consumption is 30 mW from a 2.5 V supply, and a phase error of 1deg was measured