This letter proposes a CMOS injection-locked frequency divider (ILFD) fabricated in a 0.35-μm CMOS process.The ILFD circuit is realized with a cross-coupled CMOS LC-tank oscillator, and the external injection is carried out through the gate of a waffle MOSFET. The self-oscillating ILFD is injection-locked by second-/fourth-harmonic input to obtain the division order of two/four. Measurement results show that at the supply voltage of 0.9 V and at the incident power of 0 dBm, the locking range is from the incident frequency 4.25 to 6.35 GHz in the divide-by-2 mode. The locking range is from the incident frequency 10.75 to 11.25 GHz in the divide-by-4 mode. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26064