The cerebellum is an essential structure for the control of movement. It sends abundant ascending projections to the cerebral cortex via the thalamus, but its contribution to cortical activity remains largely unknown. Here we studied its influence on cortical neuronal activity in freely moving rats. We demonstrate an excitatory action of the cerebellum on the motor thalamus and the motor cortex. We also show that cerebellar inactivation disrupts the gamma-band coherence of local field potential between the sensory and motor cortices during whisking. In contrast, phase locking of neuronal activities to local gamma oscillations was preserved in the sensory and motor cortices by cerebellar inactivation. These results indicate that the cerebellum contributes to coordinated sensorimotor cortical activities during motor activation and thus participates in the multiregional cortical processing of information.