We present a two cases of parkinsonism that appeared after shunt revision in obstructive hydrocephalus patients. Case 1 was a 59-year-old man and case 2 was a 32-year-old woman. Parkinsonism appeared in both cases after 3 or 4 shunt revisions within a period of three months. Treatment with bromocriptine, amantadine and L-dops had no effect, but the parkinsonism dramatically improved with administration of L-dopa. It was thought that repeated dilatation and collapse of the third ventricle in a short period of time might have caused concussion of the nigrostriatal pathway, resulting in reversible function loss of the nigrostriatal pathway.