This paper presents simulation and implementation results of a fine frequency tracking loop optimized for Multiple-Input Multiple-Output (MIMO), Code Division Multiple Access (CDMA) receivers. The proposed tracking loop exploits spatial diversity and multi-threshold recovery schemes to improve the loop's robustness, convergence time and accuracy. Comprehensive simulation results in a frequency-selective Rayleigh fading channel are presented, as well as implementation results using a 0.18 um CMOS technology.