High frequency stimulation (HFS) of the subthalamic nucleus (STN) is a well established therapeutic approach for the treatment of late-stage Parkinson's disease (PD). Although the underlying cause of PD remains a mystery, changes in firing rate in the basal ganglia nuclei have been related to PD symptoms. Moreover, the results of several experimental studies suggest that oscillatory activity co-varies with the normal and parkinsonian states indicating a modification of the dynamic properties of the basal ganglia network that might underlie the onset or worsening of PD symptoms. We here investigated the impact of STN-HFS on firing rate and oscillatory activity in the STN network in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned non-human primates by using simultaneous extracellular single-unit recordings. STN-HFS reduced (i) the firing rate of STN neurons,(ii) the abnormal oscillatory activity at low frequencies at an individual STN neuron level and between pairs of STN neurons and imposed (iii) single neuron and synchronized oscillatory activity at the stimulation frequency. These results suggest that STN-HFS might override the abnormal oscillatory activity in the cortex-basal ganglia-thalamus-cortex motor loop by creating a new oscillatory state, eventually reducing PD symptoms. However, a solid causal link between oscillatory activity in any frequency band and clinical symptoms is still lacking, making future studies indispensable.