A 60-GHz millimeter-wave voltage-controlled oscillator (VCO) using transformer-tuning technique is presented in this paper. In order to provide wider tuning range in V-band, the transformer-tuning method is employed instead of the varactor-tuning in a conventional LC tank. The proposed VCO exhibits a frequency tuning range of ±3.03 GHz in the vicinity of 56.07 GHz. The measured phase noise at 1-MHz offset is -91.59 dBc/Hz and the minimum measured output power is -5.63 dBm. Operated at a supply voltage of 1 V, the power consumption of VCO core and entire circuit blocks including buffers are 15.85 mW and 48.25 mW, respectively. This chip has been fabricated in TSMC 90 nm CMOS process.