Patients undergoing posterior fossa surgery in sitting position have been reported to suffer from venous air embolism, hemodynamic instability, spinal cord and lower brainstem infarctions, and pneumocephalus. Although parkinsonism has been presented secondary to subdural hematoma or effusion, there are no reports about parkinsonism related to tension pneumocephalus and subdural effusion following to surgical removal of the vestibular schwannoma. Herein, we present two patients with acute onset parkinsonism symptoms that appeared after vestibular schwannoma surgery performed in sitting position. Both patients had no extrapyramidal signs and symptoms on preoperative examination. Our first case had frontal subdural pneumocephalus and effusion, and second one similarly had tension pneumocephalus in the ventricular space. In both cases, the compression of the intracranial air on the frontobasal circuit (frontocortical-striatal-pallidal-thalamic-cortical loop) caused to parkinsonism. We concluded that secondary parkinsonism could occur with dysfunction of the circuits linking the frontobasal pathway resulting in compressive effect of tension pneumocephalus.