In two monkeys, we recorded spontaneous eye movements before and after ablation of the cerebellar nodulus and uvula (Nod/Uv). In both monkeys, there was an increase in upward ocular drift (downbeat nystagmus [DBN]) in darkness (M1: 1.5 degrees/s pre, 3.4 degrees/s post; M2: 1.3 degrees/s pre, 7.0 degrees/s post), but not in light. There was little effect of orbital position on drift velocity. These findings suggest that the Nod/Uv may play a role in the bias component of DBN.