A quantitative analysis of simple spike activity of Purkinje cells (P-cells) in the cerebellum of awake monkeys suggested their possible contribution in motor control. Simple spike activities of ventral parafloccular P-cells were recorded during short-latency ocular following responses. The relationship between the firing frequency of these P-cells and the simultaneously recorded eye movements during ocular following was analyzed by using a linear time-series regression method. The result suggests that ventral parafloccular P-cells contribute to the dynamic (velocity and acceleration) rather than the static (position) control of eye movements.